| 1998-03-31 | vs LAN | 1 | W 6-0 | 1-0 | 1 | 47,972 | Todd Stottlemyre | Ramon Martinez | Todd Stottlemyre | Ramon Martinez | | 6 | 0 | 6 |
| 1998-04-02 | vs LAN | 2 | W 8-5 | 2-0 | 2 | 27,414 | Cliff Politte | Chan Ho Park | Juan Acevedo | Frank Lankford | | 14 | 5 | 9 |
| 1998-04-03 | vs SDN | 3 | L 5-13 | 2-1 | 4 | 26,760 | Manny Aybar | Mark Langston | Mark Langston | Manny Aybar | | 19 | 18 | 1 |
| 1998-04-04 | vs SDN | 4 | W 8-6 | 3-1 | 3 | 34,292 | Kent Mercker | Pete Smith | Kent Mercker | Pete Smith | Kent Bottenfield | 27 | 24 | 3 |
| 1998-04-05 | vs SDN | 5 | L 7-8 | 3-2 | 3 | 35,499 | Todd Stottlemyre | Kevin Brown | Trevor Hoffman | Braden Looper | Dan Miceli | 34 | 32 | 2 |
| 1998-04-07 | @ COL | 6 | W 12-11 | 4-2 | 3 | 48,016 | Cliff Politte | Pedro Astacio | Cliff Politte | Pedro Astacio | Kent Bottenfield | 46 | 43 | 3 |
| 1998-04-08 | @ COL | 7 | W 13-9 | 5-2 | 3 | 48,020 | Manny Aybar | Jamey Wright | Manny Aybar | Jamey Wright | | 59 | 52 | 7 |
| 1998-04-09 | @ COL | 8 | W 7-5 | 6-2 | 3 | 46,579 | Kent Mercker | Mark Thompson | Mike Busby | Curt Leskanic | Jeff Brantley | 66 | 57 | 9 |
| 1998-04-10 | @ SFN | 9 | L 3-5 | 6-3 | 3 | 15,556 | Todd Stottlemyre | Danny Darwin | Julian Tavarez | John Frascatore | Robb Nen | 69 | 62 | 7 |
| 1998-04-11 | @ SFN | 10 | W 7-2 | 7-3 | 3 | 23,795 | Matt Morris | Shawn Estes | Kent Bottenfield | Shawn Estes | | 76 | 64 | 12 |
| 1998-04-12 | @ SFN | 11 | L 1-2 | 7-4 | 3 | 17,683 | Cliff Politte | Orel Hershiser | Robb Nen | John Frascatore | | 77 | 66 | 11 |
| 1998-04-13 | @ SFN | 12 | L 2-8 | 7-5 | 3 | 14,426 | Manny Aybar | Kirk Rueter | Kirk Rueter | Manny Aybar | | 79 | 74 | 5 |
| 1998-04-14 | vs ARI | 13 | W 15-5 | 8-5 | 3 | 31,477 | Kent Mercker | Jeff Suppan | Mike Busby | Clint Sodowsky | | 94 | 79 | 15 |
| 1998-04-16 | vs ARI | 14 | W 5-4 | 9-6 | 3 | 0 | Todd Stottlemyre | Joel Adamson | Todd Stottlemyre | Joel Adamson | Jeff Brantley | 99 | 83 | 16 |
| 1998-04-16 | vs ARI | 15 | L 2-8 | 9-6 | 3 | 32,039 | Donovan Osborne | Andy Benes | Andy Benes | Donovan Osborne | | 101 | 91 | 10 |
| 1998-04-17 | vs PHI | 16 | W 8-5 | 10-6 | 2 | 33,995 | Cliff Politte | Garrett Stephenson | Cliff Politte | Matt Whiteside | Kent Bottenfield | 109 | 96 | 13 |
| 1998-04-18 | vs PHI | 17 | W 6-5 | 11-6 | 2 | 38,848 | Manny Aybar | Mike Grace | Manny Aybar | Mike Grace | Jeff Brantley | 115 | 101 | 14 |
| 1998-04-19 | vs PHI | 18 | W 3-2 | 12-6 | 2 | 36,819 | Kent Mercker | Matt Beech | Kent Mercker | Matt Beech | Juan Acevedo | 118 | 103 | 15 |
| 1998-04-21 | @ MON | 19 | W 5-3 | 13-6 | 2 | 7,384 | Todd Stottlemyre | Trey Moore | Todd Stottlemyre | Trey Moore | Jeff Brantley | 123 | 106 | 17 |
| 1998-04-22 | @ MON | 20 | L 2-3 | 13-7 | 2 | 7,680 | Donovan Osborne | Carlos Perez | Ugueth Urbina | Kent Bottenfield | | 125 | 109 | 16 |
| 1998-04-23 | @ MON | 21 | L 2-5 | 13-8 | 2 | 7,480 | Cliff Politte | Dustin Hermanson | Dustin Hermanson | Cliff Politte | Ugueth Urbina | 127 | 114 | 13 |
| 1998-04-24 | @ PHI | 22 | L 4-8 | 13-9 | 2 | 15,208 | Kent Mercker | Mike Grace | Matt Whiteside | Kent Mercker | | 131 | 122 | 9 |
| 1998-04-25 | @ PHI | 23 | W 8-5 | 14-9 | 2 | 22,777 | Manny Aybar | Matt Beech | Mark Petkovsek | Jerry Spradlin | Jeff Brantley | 139 | 127 | 12 |
| 1998-04-26 | @ PHI | 24 | L 3-9 | 14-10 | 3 | 27,917 | Todd Stottlemyre | Curt Schilling | Curt Schilling | Todd Stottlemyre | | 142 | 136 | 6 |
| 1998-04-27 | vs MON | 25 | W 7-0 | 15-10 | 3 | 24,548 | Donovan Osborne | Carlos Perez | Donovan Osborne | Carlos Perez | | 149 | 136 | 13 |
| 1998-04-29 | vs MON | 26 | W 13-7 | 16-10 | 3 | 29,733 | Kent Mercker | Miguel Batista | Mike Busby | Steve Kline | | 162 | 143 | 19 |
| 1998-04-30 | @ CHN | 27 | L 3-8 | 16-11 | 3 | 24,210 | Mark Petkovsek | Kerry Wood | Kerry Wood | Mark Petkovsek | | 165 | 151 | 14 |
| 1998-05-01 | @ CHN | 28 | L 5-6 | 16-12 | 3 | 25,598 | Todd Stottlemyre | Geremi Gonzalez | Geremi Gonzalez | Todd Stottlemyre | Rod Beck | 170 | 157 | 13 |
| 1998-05-02 | @ CHN | 29 | L 3-4 | 16-13 | 4 | 38,430 | Donovan Osborne | Steve Trachsel | Terry Adams | Kent Bottenfield | | 173 | 161 | 12 |
| 1998-05-03 | @ CHN | 30 | W 8-5 | 17-13 | 3 | 38,571 | Cliff Politte | Kevin Tapani | Mark Petkovsek | Terry Mulholland | Jeff Brantley | 181 | 166 | 15 |
| 1998-05-05 | @ PIT | 31 | L 2-5 | 17-14 | 3 | 10,329 | Kent Mercker | Francisco Cordova | Francisco Cordova | Kent Mercker | Rich Loiselle | 183 | 171 | 12 |
| 1998-05-06 | @ PIT | 32 | L 0-5 | 17-15 | 4 | 12,051 | Todd Stottlemyre | Jason Schmidt | Jason Schmidt | Todd Stottlemyre | | 183 | 176 | 7 |
| 1998-05-07 | @ NYN | 33 | L 1-4 | 17-16 | 4 | 14,715 | Donovan Osborne | Masato Yoshii | Masato Yoshii | Donovan Osborne | John Franco | 184 | 180 | 4 |
| 1998-05-08 | @ NYN | 34 | L 2-9 | 17-17 | 5 | 16,132 | Cliff Politte | Rick Reed | Rick Reed | Cliff Politte | | 186 | 189 | -3 |
| 1998-05-11 | vs MIL | 35 | W 7-0 | 18-17 | 4 | 34,744 | Todd Stottlemyre | Scott Karl | Todd Stottlemyre | Scott Karl | | 193 | 189 | 4 |
| 1998-05-12 | vs MIL | 36 | W 6-5 | 19-17 | 4 | 25,680 | Kent Mercker | Paul Wagner | Mike Busby | Doug Jones | | 199 | 194 | 5 |
| 1998-05-13 | vs ATL | 37 | L 2-10 | 19-18 | 4 | 31,532 | Cliff Politte | Tom Glavine | Tom Glavine | Cliff Politte | | 201 | 204 | -3 |
| 1998-05-14 | vs ATL | 38 | L 3-7 | 19-19 | 5 | 32,119 | Mark Petkovsek | Kevin Millwood | John Rocker | Juan Acevedo | | 204 | 211 | -7 |
| 1998-05-15 | vs FLO | 39 | L 7-8 | 19-20 | 5 | 45,451 | Brady Raggio | Brian Meadows | Brian Meadows | Brady Raggio | Jay Powell | 211 | 219 | -8 |
| 1998-05-16 | vs FLO | 40 | W 5-4 | 20-20 | 5 | 41,464 | Todd Stottlemyre | Livan Hernandez | Todd Stottlemyre | Vic Darensbourg | | 216 | 223 | -7 |
| 1998-05-17 | vs FLO | 41 | W 13-4 | 21-20 | 4 | 41,836 | Kent Mercker | Chris Hammond | Kent Mercker | Chris Hammond | | 229 | 227 | 2 |
| 1998-05-18 | vs FLO | 42 | L 3-7 | 21-21 | 4 | 36,820 | Manny Aybar | Jesus Sanchez | Jesus Sanchez | Manny Aybar | | 232 | 234 | -2 |
| 1998-05-19 | @ PHI | 43 | W 10-8 | 22-21 | 4 | 16,541 | Mark Petkovsek | Tyler Green | John Frascatore | Wayne Gomes | Juan Acevedo | 242 | 242 | 0 |
| 1998-05-20 | @ PHI | 44 | W 8-5 | 23-21 | 4 | 21,347 | Mike Busby | Mark Portugal | Mike Busby | Mark Portugal | Jeff Brantley | 250 | 247 | 3 |
| 1998-05-21 | @ PHI | 45 | L 3-4 | 23-22 | 4 | 22,706 | Todd Stottlemyre | Mike Grace | Mike Grace | Todd Stottlemyre | Mark Leiter | 253 | 251 | 2 |
| 1998-05-22 | vs SFN | 46 | W 4-3 | 24-22 | 3 | 47,549 | Kent Mercker | Mark Gardner | Curtis King | Julian Tavarez | | 257 | 254 | 3 |
| 1998-05-23 | vs SFN | 47 | W 11-10 | 25-22 | 3 | 39,333 | Manny Aybar | Danny Darwin | Lance Painter | John Johnstone | Curtis King | 268 | 264 | 4 |
| 1998-05-24 | vs SFN | 48 | L 6-9 | 25-23 | 3 | 45,864 | Mark Petkovsek | Shawn Estes | Jim Poole | Kent Mercker | Steve Reed | 274 | 273 | 1 |
| 1998-05-25 | vs COL | 49 | L 1-6 | 25-24 | 3 | 42,038 | Mike Busby | John Thomson | John Thomson | Mike Busby | | 275 | 279 | -4 |
| 1998-05-27 | vs COL | 50 | W 2-1 | 26-24 | 3 | 34,211 | Todd Stottlemyre | Darryl Kile | Todd Stottlemyre | Darryl Kile | Jeff Brantley | 277 | 280 | -3 |
| 1998-05-28 | vs COL | 51 | W 4-1 | 27-24 | 3 | 37,989 | Kent Mercker | Jamey Wright | Kent Mercker | Jamey Wright | Curtis King | 281 | 281 | 0 |
| 1998-05-29 | @ SDN | 52 | W 8-3 | 28-24 | 3 | 36,648 | Mark Petkovsek | Joey Hamilton | Mark Petkovsek | Joey Hamilton | | 289 | 284 | 5 |
| 1998-05-30 | @ SDN | 53 | L 2-3 | 28-25 | 3 | 54,089 | Juan Acevedo | Andy Ashby | Andy Ashby | Jeff Brantley | | 291 | 287 | 4 |
| 1998-05-31 | @ SDN | 54 | L 3-7 | 28-26 | 4 | 42,618 | Sean Lowe | Kevin Brown | Kevin Brown | Sean Lowe | | 294 | 294 | 0 |
| 1998-06-01 | @ SDN | 55 | L 2-3 | 28-27 | 4 | 22,156 | Todd Stottlemyre | Sterling Hitchcock | Sterling Hitchcock | Todd Stottlemyre | Trevor Hoffman | 296 | 297 | -1 |
| 1998-06-02 | @ LAN | 56 | W 7-4 | 29-27 | 3 | 36,367 | Kent Mercker | Darren Dreifort | Kent Mercker | Darren Dreifort | Jeff Brantley | 303 | 301 | 2 |
| 1998-06-03 | @ LAN | 57 | L 4-7 | 29-28 | 3 | 35,647 | Mark Petkovsek | Ramon Martinez | Ramon Martinez | Mark Petkovsek | Scott Radinsky | 307 | 308 | -1 |
| 1998-06-04 | @ LAN | 58 | L 2-3 | 29-29 | 4 | 41,181 | Juan Acevedo | Chan Ho Park | Scott Radinsky | Jeff Brantley | | 309 | 311 | -2 |
| 1998-06-05 | vs SFN | 59 | L 2-3 | 29-30 | 5 | 43,239 | Kent Bottenfield | Orel Hershiser | Orel Hershiser | Kent Bottenfield | Robb Nen | 311 | 314 | -3 |
| 1998-06-06 | vs SFN | 60 | L 4-5 | 29-31 | 5 | 47,333 | Todd Stottlemyre | Kirk Rueter | Rich Rodriguez | Sean Lowe | | 315 | 319 | -4 |
| 1998-06-07 | vs SFN | 61 | L 5-6 | 29-32 | 5 | 41,576 | Kent Mercker | Mark Gardner | Mark Gardner | Kent Mercker | Robb Nen | 320 | 325 | -5 |
| 1998-06-08 | @ CHA | 62 | L 6-8 | 29-33 | 5 | 23,087 | Mark Petkovsek | Jason Bere | Jason Bere | Mark Petkovsek | Matt Karchner | 326 | 333 | -7 |
| 1998-06-09 | @ CHA | 63 | W 5-4 | 30-33 | 5 | 15,295 | Juan Acevedo | Jaime Navarro | Lance Painter | Jaime Navarro | Jeff Brantley | 331 | 337 | -6 |
| 1998-06-10 | @ CHA | 64 | L 8-10 | 30-34 | 5 | 16,151 | Kent Bottenfield | Jim Parque | Matt Karchner | Sean Lowe | | 339 | 347 | -8 |
| 1998-06-12 | @ ARI | 65 | W 9-4 | 31-34 | 5 | 48,169 | Todd Stottlemyre | Andy Benes | Todd Stottlemyre | Andy Benes | | 348 | 351 | -3 |
| 1998-06-13 | @ ARI | 66 | L 4-7 | 31-35 | 5 | 48,172 | Kent Mercker | Brian Anderson | Russ Springer | Jeff Brantley | Gregg Olson | 352 | 358 | -6 |
| 1998-06-14 | @ ARI | 67 | W 2-0 | 32-35 | 5 | 48,166 | Mark Petkovsek | Willie Blair | Mark Petkovsek | Willie Blair | Kent Bottenfield | 354 | 358 | -4 |
| 1998-06-16 | @ HOU | 68 | W 9-4 | 33-35 | 5 | 34,822 | Juan Acevedo | Pete Schourek | Juan Acevedo | Pete Schourek | | 363 | 362 | 1 |
| 1998-06-17 | @ HOU | 69 | L 5-6 | 33-36 | 5 | 37,147 | Todd Stottlemyre | Jose Lima | C.J. Nitkowski | Jeff Brantley | | 368 | 368 | 0 |
| 1998-06-18 | @ HOU | 70 | W 7-6 | 34-36 | 5 | 43,806 | Kent Bottenfield | Shane Reynolds | Kent Bottenfield | Shane Reynolds | Rich Croushore | 375 | 374 | 1 |
| 1998-06-19 | vs ARI | 71 | W 5-0 | 35-36 | 4 | 44,949 | Mark Petkovsek | Willie Blair | Mark Petkovsek | Willie Blair | | 380 | 374 | 6 |
| 1998-06-20 | vs ARI | 72 | W 4-2 | 36-36 | 4 | 47,632 | Manny Aybar | Amaury Telemaco | Manny Aybar | Willie Banks | Rich Croushore | 384 | 376 | 8 |
| 1998-06-21 | vs ARI | 73 | W 5-4 | 37-36 | 3 | 45,517 | Juan Acevedo | Omar Daal | Brady Raggio | Clint Sodowsky | Jeff Brantley | 389 | 380 | 9 |
| 1998-06-22 | vs DET | 74 | W 4-1 | 38-36 | 3 | 40,172 | Todd Stottlemyre | Bryce Florie | Todd Stottlemyre | Bryce Florie | Rich Croushore | 393 | 381 | 12 |
| 1998-06-23 | vs DET | 75 | L 1-8 | 38-37 | 4 | 38,371 | Kent Bottenfield | Justin Thompson | Justin Thompson | Kent Bottenfield | | 394 | 389 | 5 |
| 1998-06-24 | @ CLE | 76 | L 3-14 | 38-38 | 4 | 43,321 | Mark Petkovsek | Jaret Wright | Jaret Wright | Mark Petkovsek | | 397 | 403 | -6 |
| 1998-06-25 | @ CLE | 77 | L 2-8 | 38-39 | 4 | 43,309 | Manny Aybar | Dave Burba | Dave Burba | Manny Aybar | | 399 | 411 | -12 |
| 1998-06-26 | @ MIN | 78 | L 1-5 | 38-40 | 4 | 29,089 | Juan Acevedo | Mike Morgan | Greg Swindell | Juan Acevedo | | 400 | 416 | -16 |
| 1998-06-27 | @ MIN | 79 | W 7-2 | 39-40 | 4 | 35,002 | Todd Stottlemyre | Eric Milton | Todd Stottlemyre | Eric Milton | | 407 | 418 | -11 |
| 1998-06-28 | @ MIN | 80 | L 2-3 | 39-41 | 4 | 29,110 | Kent Bottenfield | Bob Tewksbury | Hector Carrasco | Kent Bottenfield | Rick Aguilera | 409 | 421 | -12 |
| 1998-06-30 | vs KCA | 81 | L 1-6 | 39-42 | 4 | 41,801 | Manny Aybar | Glendon Rusch | Glendon Rusch | Manny Aybar | Scott Service | 410 | 427 | -17 |
| 1998-07-01 | vs KCA | 82 | L 4-6 | 39-43 | 4 | 36,144 | Kent Mercker | Tim Belcher | Tim Belcher | Kent Mercker | Jeff Montgomery | 414 | 433 | -19 |
| 1998-07-02 | vs KCA | 83 | W 3-0 | 40-43 | 4 | 42,803 | Juan Acevedo | Hipolito Pichardo | Juan Acevedo | Hipolito Pichardo | Jeff Brantley | 417 | 433 | -16 |
| 1998-07-03 | @ CIN | 84 | L 3-6 | 40-44 | 4 | 41,302 | Todd Stottlemyre | Mike Remlinger | Mike Remlinger | Todd Stottlemyre | Jeff Shaw | 420 | 439 | -19 |
| 1998-07-04 | @ CIN | 85 | L 4-5 | 40-45 | 4 | 26,200 | Kent Bottenfield | Steve Parris | Danny Graves | Rich Croushore | | 424 | 444 | -20 |
| 1998-07-05 | @ CIN | 86 | L 1-6 | 40-46 | 4 | 28,830 | Kent Mercker | Brett Tomko | Brett Tomko | Kent Mercker | | 425 | 450 | -25 |
| 1998-07-09 | vs HOU | 87 | L 4-5 | 40-47 | 4 | 34,398 | Todd Stottlemyre | Shane Reynolds | Shane Reynolds | Todd Stottlemyre | Billy Wagner | 429 | 455 | -26 |
| 1998-07-10 | vs HOU | 88 | W 6-3 | 41-47 | 4 | 44,655 | Matt Morris | Mike Hampton | Curtis King | C.J. Nitkowski | Jeff Brantley | 435 | 458 | -23 |
| 1998-07-11 | vs HOU | 89 | W 4-3 | 42-47 | 4 | 45,760 | Kent Mercker | Jose Lima | Lance Painter | Billy Wagner | | 439 | 461 | -22 |
| 1998-07-12 | vs HOU | 90 | W 6-4 | 43-47 | 4 | 45,485 | Juan Acevedo | Sean Bergman | Juan Acevedo | Sean Bergman | Rich Croushore | 445 | 465 | -20 |
| 1998-07-13 | vs CIN | 91 | L 5-6 | 43-48 | 4 | 37,258 | Kent Bottenfield | Scott Winchester | Gabe White | Bobby Witt | | 450 | 471 | -21 |
| 1998-07-14 | vs CIN | 92 | L 4-7 | 43-49 | 5 | 31,183 | Todd Stottlemyre | Steve Parris | Scott Sullivan | Todd Stottlemyre | Danny Graves | 454 | 478 | -24 |
| 1998-07-15 | vs CIN | 93 | L 2-4 | 43-50 | 5 | 32,321 | Matt Morris | Brett Tomko | Gabe White | John Frascatore | | 456 | 482 | -26 |
| 1998-07-16 | vs LAN | 94 | L 2-8 | 43-51 | 5 | 35,324 | Kent Mercker | Ismael Valdez | Ismael Valdez | Kent Mercker | | 458 | 490 | -32 |
| 1998-07-17 | vs LAN | 95 | W 4-1 | 44-51 | 5 | 39,191 | Juan Acevedo | Brian Bohanon | Juan Acevedo | Brian Bohanon | Rich Croushore | 462 | 491 | -29 |
| 1998-07-18 | vs LAN | 96 | L 8-10 | 44-52 | 5 | 44,598 | Kent Bottenfield | Dave Mlicki | Mark Guthrie | Jeff Brantley | Jeff Shaw | 470 | 501 | -31 |
| 1998-07-19 | vs LAN | 97 | W 5-4 | 45-52 | 4 | 47,006 | Todd Stottlemyre | Chan Ho Park | Mark Petkovsek | Scott Radinsky | | 475 | 505 | -30 |
| 1998-07-20 | @ SDN | 98 | W 13-1 | 46-52 | 4 | 32,339 | Matt Morris | Mark Langston | Matt Morris | Mark Langston | | 488 | 506 | -18 |
| 1998-07-21 | @ SDN | 99 | L 3-6 | 46-53 | 4 | 37,145 | Kent Mercker | Kevin Brown | Kevin Brown | Kent Mercker | Trevor Hoffman | 491 | 512 | -21 |
| 1998-07-22 | @ SFN | 100 | W 3-2 | 47-53 | 4 | 40,147 | Bobby Witt | Kirk Rueter | Bobby Witt | Kirk Rueter | Rich Croushore | 494 | 514 | -20 |
| 1998-07-23 | @ SFN | 101 | W 8-1 | 48-53 | 4 | 46,393 | Kent Bottenfield | Danny Darwin | Kent Bottenfield | Danny Darwin | | 502 | 515 | -13 |
| 1998-07-24 | @ COL | 102 | L 3-12 | 48-54 | 4 | 48,303 | Todd Stottlemyre | Darryl Kile | Darryl Kile | Todd Stottlemyre | | 505 | 527 | -22 |
| 1998-07-25 | @ COL | 103 | L 2-5 | 48-55 | 5 | 48,323 | Matt Morris | Jamey Wright | Chuck McElroy | Matt Morris | Mike DeJean | 507 | 532 | -25 |
| 1998-07-26 | @ COL | 104 | W 3-1 | 49-55 | 4 | 48,288 | Kent Mercker | John Thomson | Kent Mercker | John Thomson | Rich Croushore | 510 | 533 | -23 |
| 1998-07-28 | vs MIL | 105 | L 10-13 | 49-56 | 4 | 36,812 | Kent Bottenfield | Brad Woodall | David Weathers | Rich Croushore | Bob Wickman | 520 | 546 | -26 |
| 1998-07-29 | vs MIL | 106 | L 1-2 | 49-57 | 5 | 36,672 | Bobby Witt | Steve Woodard | Steve Woodard | Bobby Witt | Bob Wickman | 521 | 548 | -27 |
| 1998-07-30 | vs MIL | 107 | W 3-2 | 50-57 | 4 | 35,766 | Matt Morris | Scott Karl | Matt Morris | Scott Karl | Rich Croushore | 524 | 550 | -26 |
| 1998-07-31 | @ ATL | 108 | W 3-2 | 51-57 | 4 | 50,662 | Kent Mercker | Greg Maddux | Kent Mercker | Greg Maddux | Lance Painter | 527 | 552 | -25 |
| 1998-08-01 | @ ATL | 109 | L 1-3 | 51-58 | 4 | 50,137 | Kent Bottenfield | Tom Glavine | Rudy Seanez | Rich Croushore | Kerry Ligtenberg | 528 | 555 | -27 |
| 1998-08-02 | @ ATL | 110 | L 3-4 | 51-59 | 4 | 49,296 | Bobby Witt | Kevin Millwood | Kevin Millwood | Bobby Witt | Kerry Ligtenberg | 531 | 559 | -28 |
| 1998-08-03 | @ MIL | 111 | L 5-6 | 51-60 | 4 | 31,659 | Darren Oliver | Steve Woodard | Steve Woodard | Darren Oliver | Bob Wickman | 536 | 565 | -29 |
| 1998-08-04 | @ MIL | 112 | W 2-1 | 52-60 | 4 | 28,389 | Matt Morris | Scott Karl | Matt Morris | Scott Karl | | 538 | 566 | -28 |
| 1998-08-05 | @ MIL | 113 | W 5-1 | 53-60 | 4 | 25,969 | Kent Mercker | Jeff Juden | Kent Mercker | Jeff Juden | | 543 | 567 | -24 |
| 1998-08-07 | vs CHN | 114 | W 16-3 | 54-60 | 4 | 47,911 | Kent Bottenfield | Steve Trachsel | Kent Bottenfield | Steve Trachsel | | 559 | 570 | -11 |
| 1998-08-08 | vs CHN | 115 | W 9-8 | 55-60 | 4 | 48,064 | Donovan Osborne | Mark Clark | Bobby Witt | Dave Stevens | | 568 | 578 | -10 |
| 1998-08-09 | vs CHN | 116 | W 2-1 | 56-60 | 4 | 47,798 | Darren Oliver | Don Wengert | Darren Oliver | Don Wengert | Jeff Brantley | 570 | 579 | -9 |
| 1998-08-10 | vs NYN | 117 | L 2-4 | 56-61 | 4 | 41,252 | Matt Morris | Al Leiter | Al Leiter | Matt Morris | John Franco | 572 | 583 | -11 |
| 1998-08-11 | vs NYN | 118 | L 3-8 | 56-62 | 4 | 34,489 | Kent Mercker | Bobby Jones | Bobby Jones | Kent Mercker | | 575 | 591 | -16 |
| 1998-08-12 | vs NYN | 119 | W 5-4 | 57-62 | 4 | 34,260 | Kent Bottenfield | Masato Yoshii | John Frascatore | John Franco | | 580 | 595 | -15 |
| 1998-08-14 | vs PIT | 120 | W 10-5 | 58-62 | 3 | 47,836 | Donovan Osborne | Jon Lieber | Donovan Osborne | Jon Lieber | | 590 | 600 | -10 |
| 1998-08-15 | vs PIT | 121 | W 8-7 | 59-62 | 3 | 46,817 | Darren Oliver | Chris Peters | Lance Painter | Jeff McCurry | | 598 | 607 | -9 |
| 1998-08-16 | vs PIT | 122 | L 1-4 | 59-63 | 3 | 46,904 | Matt Morris | Francisco Cordova | Francisco Cordova | Matt Morris | Jon Lieber | 599 | 611 | -12 |
| 1998-08-18 | @ CHN | 123 | L 1-4 | 59-64 | 4 | 40,249 | Kent Mercker | Steve Trachsel | Steve Trachsel | Kent Mercker | Rod Beck | 600 | 615 | -15 |
| 1998-08-19 | @ CHN | 124 | W 8-6 | 60-64 | 3 | 39,689 | Kent Bottenfield | Mark Clark | Juan Acevedo | Terry Mulholland | | 608 | 621 | -13 |
| 1998-08-20 | @ NYN | 125 | W 2-0 | 61-65 | 3 | 0 | Donovan Osborne | Willie Blair | Donovan Osborne | Willie Blair | Juan Acevedo | 610 | 621 | -11 |
| 1998-08-20 | @ NYN | 126 | L 4-5 | 61-65 | 3 | 45,308 | Darren Oliver | Rick Reed | Rick Reed | Darren Oliver | Turk Wendell | 614 | 626 | -12 |
| 1998-08-21 | @ NYN | 127 | W 10-5 | 62-66 | 3 | 0 | Matt Morris | Hideo Nomo | Matt Morris | Hideo Nomo | | 624 | 631 | -7 |
| 1998-08-21 | @ NYN | 128 | L 0-1 | 62-66 | 3 | 52,320 | Manny Aybar | Armando Reynoso | Armando Reynoso | Manny Aybar | John Franco | 624 | 632 | -8 |
| 1998-08-22 | @ PIT | 129 | L 4-14 | 62-67 | 4 | 45,082 | Bobby Witt | Francisco Cordova | Francisco Cordova | Bobby Witt | | 628 | 646 | -18 |
| 1998-08-23 | @ PIT | 130 | L 3-4 | 62-68 | 5 | 42,134 | Kent Mercker | Jason Schmidt | Jason Schmidt | Kent Mercker | Jason Christiansen | 631 | 650 | -19 |
| 1998-08-24 | @ PIT | 131 | L 5-5 | 62-69 | 5 | 28,435 | Kent Bottenfield | Todd Van Poppel | | | | 636 | 655 | -19 |
| 1998-08-25 | vs FLO | 132 | L 3-4 | 62-70 | 5 | 29,130 | Donovan Osborne | Rafael Medina | Rafael Medina | Donovan Osborne | Antonio Alfonseca | 639 | 659 | -20 |
| 1998-08-26 | vs FLO | 133 | L 6-7 | 62-71 | 5 | 30,004 | Darren Oliver | Kirt Ojala | Antonio Alfonseca | Juan Acevedo | | 645 | 666 | -21 |
| 1998-08-27 | vs ATL | 134 | L 4-6 | 62-72 | 6 | 33,889 | Matt Morris | Denny Neagle | Denny Neagle | Matt Morris | Kerry Ligtenberg | 649 | 672 | -23 |
| 1998-08-28 | vs ATL | 135 | W 5-4 | 63-72 | 6 | 45,666 | Kent Mercker | Greg Maddux | Juan Acevedo | Dennis Martinez | | 654 | 676 | -22 |
| 1998-08-29 | vs ATL | 136 | L 3-4 | 63-73 | 6 | 47,627 | Kent Bottenfield | Tom Glavine | Tom Glavine | Kent Bottenfield | Rudy Seanez | 657 | 680 | -23 |
| 1998-08-30 | vs ATL | 137 | W 8-7 | 64-73 | 6 | 44,051 | Donovan Osborne | Kevin Millwood | Mark Petkovsek | Dennis Martinez | Juan Acevedo | 665 | 687 | -22 |
| 1998-08-31 | @ FLO | 138 | W 5-3 | 65-73 | 5 | 36,584 | Darren Oliver | Kirt Ojala | Darren Oliver | Kirt Ojala | Juan Acevedo | 670 | 690 | -20 |
| 1998-09-01 | @ FLO | 139 | W 7-1 | 66-73 | 3 | 37,014 | Matt Morris | Livan Hernandez | Matt Morris | Livan Hernandez | | 677 | 691 | -14 |
| 1998-09-02 | @ FLO | 140 | W 14-4 | 67-73 | 3 | 45,170 | Kent Mercker | Jesus Sanchez | Kent Mercker | Jesus Sanchez | | 691 | 695 | -4 |
| 1998-09-04 | vs CIN | 141 | L 2-3 | 67-74 | 3 | 48,076 | Kent Bottenfield | Pete Harnisch | Pete Harnisch | John Frascatore | Gabe White | 693 | 698 | -5 |
| 1998-09-05 | vs CIN | 142 | W 7-0 | 68-74 | 3 | 47,994 | Donovan Osborne | Dennys Reyes | Donovan Osborne | Dennys Reyes | | 700 | 698 | 2 |
| 1998-09-06 | vs CIN | 143 | W 5-2 | 69-74 | 3 | 47,904 | Matt Morris | Brett Tomko | Juan Acevedo | John Hudek | | 705 | 700 | 5 |
| 1998-09-07 | vs CHN | 144 | W 3-2 | 70-74 | 3 | 42,877 | Darren Oliver | Mike Morgan | Darren Oliver | Mike Morgan | Juan Acevedo | 708 | 702 | 6 |
| 1998-09-08 | vs CHN | 145 | W 6-3 | 71-74 | 3 | 43,688 | Kent Mercker | Steve Trachsel | Kent Mercker | Steve Trachsel | Juan Acevedo | 714 | 705 | 9 |
| 1998-09-09 | @ CIN | 146 | L 3-6 | 71-75 | 3 | 51,969 | Bobby Witt | Pete Harnisch | Pete Harnisch | Bobby Witt | Danny Graves | 717 | 711 | 6 |
| 1998-09-10 | @ CIN | 147 | W 8-7 | 72-75 | 3 | 50,971 | Donovan Osborne | Mike Remlinger | Manny Aybar | Mike Remlinger | Juan Acevedo | 725 | 718 | 7 |
| 1998-09-11 | @ HOU | 148 | L 2-8 | 72-76 | 3 | 52,186 | Matt Morris | Mike Hampton | Jay Powell | Matt Morris | | 727 | 726 | 1 |
| 1998-09-12 | @ HOU | 149 | L 2-3 | 72-77 | 3 | 52,493 | Darren Oliver | Randy Johnson | Randy Johnson | Darren Oliver | Billy Wagner | 729 | 729 | 0 |
| 1998-09-13 | @ HOU | 150 | W 3-2 | 73-77 | 3 | 52,338 | Kent Mercker | Sean Bergman | Kent Mercker | Sean Bergman | Juan Acevedo | 732 | 731 | 1 |
| 1998-09-14 | vs PIT | 151 | W 7-3 | 74-77 | 3 | 42,265 | Jose Jimenez | Jason Schmidt | Jose Jimenez | Jason Schmidt | | 739 | 734 | 5 |
| 1998-09-15 | vs PIT | 152 | L 6-8 | 75-78 | 3 | 0 | Donovan Osborne | Jon Lieber | Sean Lawrence | Donovan Osborne | Rich Loiselle | 745 | 742 | 3 |
| 1998-09-15 | vs PIT | 153 | W 9-3 | 75-78 | 3 | 41,271 | Manny Aybar | Jose Silva | Manny Aybar | Jose Silva | Juan Acevedo | 754 | 745 | 9 |
| 1998-09-16 | vs PIT | 154 | W 4-0 | 76-78 | 3 | 39,758 | Matt Morris | Chris Peters | Matt Morris | Todd Van Poppel | | 758 | 745 | 13 |
| 1998-09-18 | @ MIL | 155 | W 5-2 | 77-78 | 3 | 48,194 | Darren Oliver | Rafael Roque | Darren Oliver | Rafael Roque | Juan Acevedo | 763 | 747 | 16 |
| 1998-09-19 | @ MIL | 156 | W 7-4 | 78-78 | 3 | 54,132 | Jose Jimenez | Steve Woodard | Jose Jimenez | Steve Woodard | Juan Acevedo | 770 | 751 | 19 |
| 1998-09-20 | @ MIL | 157 | W 11-6 | 79-78 | 3 | 52,831 | Kent Mercker | Scott Karl | Manny Aybar | Scott Karl | | 781 | 757 | 24 |
| 1998-09-22 | vs HOU | 158 | W 4-0 | 80-78 | 3 | 40,739 | Matt Morris | Mike Hampton | Matt Morris | Mike Hampton | | 785 | 757 | 28 |
| 1998-09-23 | vs HOU | 159 | L 1-7 | 80-79 | 3 | 38,997 | Darren Oliver | Randy Johnson | Randy Johnson | Darren Oliver | | 786 | 764 | 22 |
| 1998-09-24 | vs MON | 160 | W 6-3 | 81-79 | 3 | 41,911 | Donovan Osborne | Javier Vazquez | Donovan Osborne | Javier Vazquez | Juan Acevedo | 792 | 767 | 25 |
| 1998-09-25 | vs MON | 161 | W 6-5 | 82-79 | 3 | 48,159 | Jose Jimenez | Miguel Batista | Jose Jimenez | Shayne Bennett | Juan Acevedo | 798 | 772 | 26 |
| 1998-09-26 | vs MON | 162 | L 6-7 | 82-80 | 3 | 48,212 | Manny Aybar | Dustin Hermanson | Ugueth Urbina | Mike Busby | Rick DeHart | 804 | 779 | 25 |
| 1998-09-27 | vs MON | 163 | W 6-3 | 83-80 | 3 | 46,110 | Matt Morris | Mike Thurman | John Frascatore | Carl Pavano | Juan Acevedo | 810 | 782 | 28 |