| 1998-03-31 | @ FLO | 1 | L 6-11 | 0-1 | 2 | 41,126 | Kevin Tapani | Livan Hernandez | Livan Hernandez | Kevin Tapani | | 6 | 11 | -5 |
| 1998-04-01 | @ FLO | 2 | W 10-3 | 1-1 | 3 | 16,877 | Mark Clark | Felix Heredia | Mark Clark | Felix Heredia | | 16 | 14 | 2 |
| 1998-04-02 | @ FLO | 3 | W 8-7 | 2-1 | 3 | 17,209 | Geremi Gonzalez | Rafael Medina | Bob Patterson | Jay Powell | Rod Beck | 24 | 21 | 3 |
| 1998-04-03 | vs MON | 4 | W 6-2 | 3-1 | 1 | 39,102 | Steve Trachsel | Javier Vazquez | Steve Trachsel | Javier Vazquez | Rod Beck | 30 | 23 | 7 |
| 1998-04-04 | vs MON | 5 | W 3-1 | 4-1 | 1 | 25,436 | Terry Mulholland | Marc Valdes | Terry Mulholland | Marc Valdes | Rod Beck | 33 | 24 | 9 |
| 1998-04-05 | vs MON | 6 | W 7-2 | 5-1 | 1 | 21,854 | Kevin Tapani | Trey Moore | Kevin Tapani | Trey Moore | | 40 | 26 | 14 |
| 1998-04-06 | vs MON | 7 | W 3-2 | 6-1 | 1 | 12,506 | Mark Clark | Carlos Perez | Mark Clark | Carlos Perez | Rod Beck | 43 | 28 | 15 |
| 1998-04-07 | vs NYN | 8 | L 2-3 | 6-2 | 2 | 16,293 | Geremi Gonzalez | Al Leiter | Al Leiter | Geremi Gonzalez | John Franco | 45 | 31 | 14 |
| 1998-04-09 | vs NYN | 9 | W 8-7 | 7-2 | 1 | 17,313 | Steve Trachsel | Rick Reed | Steve Trachsel | Rick Reed | Rod Beck | 53 | 38 | 15 |
| 1998-04-10 | @ MON | 10 | W 13-0 | 8-2 | 1 | 9,982 | Kevin Tapani | Marc Valdes | Kevin Tapani | Marc Valdes | | 66 | 38 | 28 |
| 1998-04-11 | @ MON | 11 | L 4-5 | 8-3 | 1 | 20,218 | Mark Clark | Carlos Perez | Steve Kline | Terry Adams | | 70 | 43 | 27 |
| 1998-04-12 | @ MON | 12 | L 1-4 | 8-4 | 1 | 18,506 | Kerry Wood | Dustin Hermanson | Dustin Hermanson | Kerry Wood | Ugueth Urbina | 71 | 47 | 24 |
| 1998-04-14 | @ NYN | 13 | L 0-6 | 8-5 | 2 | 15,965 | Geremi Gonzalez | Al Leiter | Al Leiter | Geremi Gonzalez | | 71 | 53 | 18 |
| 1998-04-15 | @ NYN | 14 | L 1-2 | 8-6 | 3 | 16,012 | Steve Trachsel | Rick Reed | Rick Reed | Steve Trachsel | John Franco | 72 | 55 | 17 |
| 1998-04-16 | @ NYN | 15 | W 8-4 | 9-6 | 2 | 50,814 | Kevin Tapani | Dave Mlicki | Kevin Tapani | Dave Mlicki | | 80 | 59 | 21 |
| 1998-04-17 | vs LAN | 16 | L 3-11 | 9-7 | 3 | 20,175 | Mark Clark | Chan Ho Park | Chan Ho Park | Mark Clark | Frank Lankford | 83 | 70 | 13 |
| 1998-04-18 | vs LAN | 17 | W 8-1 | 10-7 | 3 | 34,652 | Kerry Wood | Hideo Nomo | Kerry Wood | Hideo Nomo | | 91 | 71 | 20 |
| 1998-04-19 | vs LAN | 18 | W 2-1 | 11-7 | 3 | 26,795 | Geremi Gonzalez | Ismael Valdez | Geremi Gonzalez | Ismael Valdez | Rod Beck | 93 | 72 | 21 |
| 1998-04-21 | vs SDN | 19 | W 5-3 | 12-7 | 3 | 20,363 | Steve Trachsel | Kevin Brown | Steve Trachsel | Kevin Brown | Rod Beck | 98 | 75 | 23 |
| 1998-04-22 | vs SDN | 20 | L 2-3 | 12-8 | 3 | 15,852 | Kevin Tapani | Joey Hamilton | Brian Boehringer | Amaury Telemaco | Carlos Reyes | 100 | 78 | 22 |
| 1998-04-23 | vs SDN | 21 | L 1-4 | 12-9 | 3 | 20,276 | Mark Clark | Andy Ashby | Andy Ashby | Mark Clark | Trevor Hoffman | 101 | 82 | 19 |
| 1998-04-24 | @ LAN | 22 | L 4-12 | 12-10 | 3 | 36,674 | Kerry Wood | Ismael Valdez | Ismael Valdez | Kerry Wood | | 105 | 94 | 11 |
| 1998-04-25 | @ LAN | 23 | L 2-3 | 12-11 | 4 | 53,755 | Geremi Gonzalez | Darren Dreifort | Mark Guthrie | Geremi Gonzalez | Scott Radinsky | 107 | 97 | 10 |
| 1998-04-26 | @ LAN | 24 | L 3-4 | 12-12 | 4 | 49,069 | Steve Trachsel | Ramon Martinez | Brad Clontz | Marc Pisciotta | | 110 | 101 | 9 |
| 1998-04-27 | @ SDN | 25 | W 3-1 | 13-12 | 4 | 20,106 | Kevin Tapani | Joey Hamilton | Kevin Tapani | Joey Hamilton | Rod Beck | 113 | 102 | 11 |
| 1998-04-28 | @ SDN | 26 | L 3-7 | 13-13 | 4 | 21,024 | Mark Clark | Andy Ashby | Andy Ashby | Mark Clark | Sterling Hitchcock | 116 | 109 | 7 |
| 1998-04-30 | vs SLN | 27 | W 8-3 | 14-13 | 4 | 24,210 | Kerry Wood | Mark Petkovsek | Kerry Wood | Mark Petkovsek | | 124 | 112 | 12 |
| 1998-05-01 | vs SLN | 28 | W 6-5 | 15-13 | 4 | 25,598 | Geremi Gonzalez | Todd Stottlemyre | Geremi Gonzalez | Todd Stottlemyre | Rod Beck | 130 | 117 | 13 |
| 1998-05-02 | vs SLN | 29 | W 4-3 | 16-13 | 3 | 38,430 | Steve Trachsel | Donovan Osborne | Terry Adams | Kent Bottenfield | | 134 | 120 | 14 |
| 1998-05-03 | vs SLN | 30 | L 5-8 | 16-14 | 4 | 38,571 | Kevin Tapani | Cliff Politte | Mark Petkovsek | Terry Mulholland | Jeff Brantley | 139 | 128 | 11 |
| 1998-05-05 | vs HOU | 31 | L 5-10 | 16-15 | 4 | 21,431 | Mark Clark | Jose Lima | Jose Lima | Mark Clark | C.J. Nitkowski | 144 | 138 | 6 |
| 1998-05-06 | vs HOU | 32 | W 2-0 | 17-15 | 3 | 15,758 | Kerry Wood | Shane Reynolds | Kerry Wood | Shane Reynolds | | 146 | 138 | 8 |
| 1998-05-08 | vs SFN | 33 | W 5-4 | 18-15 | 3 | 22,665 | Steve Trachsel | Mark Gardner | Amaury Telemaco | Julian Tavarez | | 151 | 142 | 9 |
| 1998-05-09 | vs SFN | 34 | L 1-5 | 19-16 | 3 | 0 | Kevin Tapani | Danny Darwin | Danny Darwin | Kevin Tapani | | 152 | 147 | 5 |
| 1998-05-09 | vs SFN | 35 | W 6-0 | 19-16 | 3 | 35,970 | Geremi Gonzalez | Shawn Estes | Geremi Gonzalez | Shawn Estes | | 158 | 147 | 11 |
| 1998-05-10 | vs SFN | 36 | L 0-3 | 19-17 | 3 | 26,710 | Mark Clark | Orel Hershiser | Orel Hershiser | Mark Clark | Robb Nen | 158 | 150 | 8 |
| 1998-05-11 | @ ARI | 37 | W 4-2 | 20-17 | 3 | 47,129 | Kerry Wood | Brian Anderson | Kerry Wood | Brian Anderson | Rod Beck | 162 | 152 | 10 |
| 1998-05-12 | @ ARI | 38 | W 7-6 | 21-17 | 2 | 45,240 | Terry Mulholland | Andy Benes | Terry Adams | Felix Rodriguez | Rod Beck | 169 | 158 | 11 |
| 1998-05-13 | @ COL | 39 | W 9-3 | 22-17 | 2 | 48,038 | Steve Trachsel | Pedro Astacio | Steve Trachsel | Pedro Astacio | | 178 | 161 | 17 |
| 1998-05-14 | @ COL | 40 | W 9-7 | 23-17 | 2 | 48,077 | Kevin Tapani | John Thomson | Kevin Tapani | John Thomson | Rod Beck | 187 | 168 | 19 |
| 1998-05-15 | @ CIN | 41 | L 3-11 | 23-18 | 2 | 21,408 | Geremi Gonzalez | Pete Harnisch | Pete Harnisch | Geremi Gonzalez | | 190 | 179 | 11 |
| 1998-05-16 | @ CIN | 42 | W 5-4 | 24-18 | 2 | 30,505 | Mark Clark | Mike Remlinger | Mark Clark | Mike Remlinger | Rod Beck | 195 | 183 | 12 |
| 1998-05-17 | @ CIN | 43 | W 10-1 | 25-18 | 2 | 33,480 | Kerry Wood | David Weathers | Kerry Wood | David Weathers | Terry Mulholland | 205 | 184 | 21 |
| 1998-05-19 | vs LAN | 44 | W 6-3 | 26-18 | 2 | 30,607 | Steve Trachsel | Chan Ho Park | Steve Trachsel | Chan Ho Park | Rod Beck | 211 | 187 | 24 |
| 1998-05-20 | vs LAN | 45 | W 5-0 | 27-18 | 2 | 24,245 | Kevin Tapani | Hideo Nomo | Kevin Tapani | Hideo Nomo | | 216 | 187 | 29 |
| 1998-05-21 | vs LAN | 46 | L 3-7 | 27-19 | 2 | 22,616 | Geremi Gonzalez | Ismael Valdez | Ismael Valdez | Terry Adams | Antonio Osuna | 219 | 194 | 25 |
| 1998-05-22 | @ ATL | 47 | L 2-8 | 27-20 | 2 | 43,576 | Mark Clark | Greg Maddux | Greg Maddux | Mark Clark | | 221 | 202 | 19 |
| 1998-05-23 | @ ATL | 48 | W 10-6 | 28-20 | 2 | 50,189 | Kerry Wood | John Smoltz | Rod Beck | Brian Edmondson | | 231 | 208 | 23 |
| 1998-05-24 | @ ATL | 49 | L 1-2 | 28-21 | 2 | 48,580 | Steve Trachsel | Tom Glavine | Tom Glavine | Terry Adams | | 232 | 210 | 22 |
| 1998-05-25 | @ ATL | 50 | L 5-9 | 28-22 | 2 | 33,704 | Kevin Tapani | Kevin Millwood | Kevin Millwood | Kevin Tapani | | 237 | 219 | 18 |
| 1998-05-27 | vs PHI | 51 | L 5-10 | 28-23 | 2 | 19,354 | Geremi Gonzalez | Mike Grace | Mike Grace | Geremi Gonzalez | | 242 | 229 | 13 |
| 1998-05-28 | vs PHI | 52 | L 7-8 | 28-24 | 2 | 25,285 | Mark Clark | Curt Schilling | Darrin Winston | Rod Beck | Mark Leiter | 249 | 237 | 12 |
| 1998-05-29 | vs ATL | 53 | W 5-3 | 29-24 | 2 | 38,010 | Kerry Wood | Tom Glavine | Terry Adams | John Rocker | | 254 | 240 | 14 |
| 1998-05-30 | vs ATL | 54 | W 9-8 | 30-24 | 2 | 39,817 | Steve Trachsel | Kevin Millwood | Steve Trachsel | Kevin Millwood | Bob Patterson | 263 | 248 | 15 |
| 1998-05-31 | vs ATL | 55 | W 4-2 | 31-24 | 2 | 29,285 | Kevin Tapani | Denny Neagle | Kevin Tapani | Denny Neagle | Rod Beck | 267 | 250 | 17 |
| 1998-06-01 | vs FLO | 56 | W 10-2 | 32-24 | 2 | 25,538 | Geremi Gonzalez | Ryan Dempster | Geremi Gonzalez | Ryan Dempster | | 277 | 252 | 25 |
| 1998-06-02 | vs FLO | 57 | W 2-1 | 33-24 | 2 | 16,875 | Mark Clark | Brian Meadows | Terry Adams | Felix Heredia | | 279 | 253 | 26 |
| 1998-06-03 | vs FLO | 58 | W 5-1 | 34-24 | 2 | 20,942 | Kerry Wood | Livan Hernandez | Kerry Wood | Livan Hernandez | | 284 | 254 | 30 |
| 1998-06-05 | vs CHA | 59 | W 6-5 | 35-24 | 1 | 38,097 | Steve Trachsel | Jim Parque | Terry Mulholland | Tony Castillo | | 290 | 259 | 31 |
| 1998-06-06 | vs CHA | 60 | W 7-6 | 36-24 | 1 | 38,232 | Kevin Tapani | Scott Eyre | Kevin Tapani | Scott Eyre | Rod Beck | 297 | 265 | 32 |
| 1998-06-07 | vs CHA | 61 | W 13-7 | 37-24 | 1 | 39,320 | Geremi Gonzalez | Mike Sirotka | Geremi Gonzalez | Mike Sirotka | | 310 | 272 | 38 |
| 1998-06-08 | @ MIN | 62 | W 8-1 | 38-24 | 1 | 18,077 | Mark Clark | LaTroy Hawkins | Mark Clark | LaTroy Hawkins | | 318 | 273 | 45 |
| 1998-06-09 | @ MIN | 63 | L 0-8 | 38-25 | 2 | 25,806 | Kerry Wood | Brad Radke | Brad Radke | Kerry Wood | | 318 | 281 | 37 |
| 1998-06-10 | @ MIN | 64 | L 1-5 | 38-26 | 2 | 15,086 | Steve Trachsel | Mike Morgan | Mike Morgan | Steve Trachsel | Rick Aguilera | 319 | 286 | 33 |
| 1998-06-12 | @ PHI | 65 | L 0-4 | 38-27 | 2 | 15,489 | Kevin Tapani | Curt Schilling | Curt Schilling | Kevin Tapani | | 319 | 290 | 29 |
| 1998-06-13 | @ PHI | 66 | W 10-8 | 39-27 | 2 | 17,115 | Geremi Gonzalez | Mark Portugal | Terry Adams | Jerry Spradlin | | 329 | 298 | 31 |
| 1998-06-14 | @ PHI | 67 | L 2-4 | 39-28 | 2 | 25,543 | Mark Clark | Carlton Loewer | Carlton Loewer | Mark Clark | | 331 | 302 | 29 |
| 1998-06-15 | vs MIL | 68 | W 6-5 | 40-28 | 2 | 37,903 | Kerry Wood | Cal Eldred | Terry Adams | Doug Jones | Rod Beck | 337 | 307 | 30 |
| 1998-06-16 | vs MIL | 69 | L 2-11 | 40-29 | 2 | 25,409 | Steve Trachsel | Brad Woodall | Brad Woodall | Steve Trachsel | | 339 | 318 | 21 |
| 1998-06-17 | vs MIL | 70 | L 5-6 | 40-30 | 2 | 28,673 | Kevin Tapani | Scott Karl | Bronswell Patrick | Kevin Tapani | Bob Wickman | 344 | 324 | 20 |
| 1998-06-18 | vs PHI | 71 | W 12-5 | 41-30 | 2 | 21,267 | Geremi Gonzalez | Mark Portugal | Geremi Gonzalez | Mark Portugal | Terry Mulholland | 356 | 329 | 27 |
| 1998-06-19 | vs PHI | 72 | L 8-9 | 41-31 | 2 | 39,592 | Mark Clark | Carlton Loewer | Jerry Spradlin | Terry Mulholland | | 364 | 338 | 26 |
| 1998-06-20 | vs PHI | 73 | W 9-4 | 42-31 | 2 | 39,761 | Kerry Wood | Matt Beech | Kerry Wood | Matt Beech | | 373 | 342 | 31 |
| 1998-06-21 | vs PHI | 74 | L 2-7 | 42-32 | 2 | 38,437 | Steve Trachsel | Tyler Green | Tyler Green | Steve Trachsel | | 375 | 349 | 26 |
| 1998-06-22 | vs CLE | 75 | L 1-3 | 42-33 | 2 | 39,556 | Kevin Tapani | Dwight Gooden | Dwight Gooden | Kevin Tapani | Michael Jackson | 376 | 352 | 24 |
| 1998-06-23 | vs CLE | 76 | L 4-5 | 42-34 | 2 | 39,006 | Geremi Gonzalez | Charles Nagy | Eric Plunk | Terry Adams | Michael Jackson | 380 | 357 | 23 |
| 1998-06-24 | @ DET | 77 | L 6-7 | 42-35 | 2 | 23,810 | Mark Clark | Seth Greisinger | Doug Brocail | Marc Pisciotta | | 386 | 364 | 22 |
| 1998-06-25 | @ DET | 78 | L 4-6 | 42-36 | 2 | 30,688 | Kerry Wood | Brian Moehler | Matt Anderson | Terry Adams | Todd Jones | 390 | 370 | 20 |
| 1998-06-26 | @ KCA | 79 | L 3-6 | 42-37 | 3 | 39,008 | Steve Trachsel | Hipolito Pichardo | Hipolito Pichardo | Steve Trachsel | Jeff Montgomery | 393 | 376 | 17 |
| 1998-06-27 | @ KCA | 80 | L 3-4 | 42-38 | 3 | 39,295 | Kevin Tapani | Jose Rosado | Scott Service | Rod Beck | | 396 | 380 | 16 |
| 1998-06-28 | @ KCA | 81 | W 6-3 | 43-38 | 3 | 34,287 | Geremi Gonzalez | Pat Rapp | Geremi Gonzalez | Pat Rapp | Rod Beck | 402 | 383 | 19 |
| 1998-06-30 | vs ARI | 82 | L 4-5 | 43-39 | 3 | 39,307 | Mark Clark | Willie Blair | Willie Blair | Mark Clark | Gregg Olson | 406 | 388 | 18 |
| 1998-07-01 | vs ARI | 83 | W 6-4 | 44-39 | 3 | 31,002 | Kerry Wood | Amaury Telemaco | Kerry Wood | Amaury Telemaco | Rod Beck | 412 | 392 | 20 |
| 1998-07-02 | vs ARI | 84 | W 3-2 | 45-39 | 2 | 29,268 | Steve Trachsel | Jeff Suppan | Steve Trachsel | Jeff Suppan | Rod Beck | 415 | 394 | 21 |
| 1998-07-03 | vs PIT | 85 | W 12-9 | 46-39 | 2 | 40,420 | Kevin Tapani | Francisco Cordova | Kevin Tapani | Francisco Cordova | Rod Beck | 427 | 403 | 24 |
| 1998-07-04 | vs PIT | 86 | W 5-4 | 47-39 | 2 | 37,780 | Geremi Gonzalez | Jason Schmidt | Marc Pisciotta | Jason Schmidt | Rod Beck | 432 | 407 | 25 |
| 1998-07-05 | vs PIT | 87 | W 7-6 | 48-39 | 2 | 38,742 | Mark Clark | Jon Lieber | Dave Stevens | Rich Loiselle | Rod Beck | 439 | 413 | 26 |
| 1998-07-09 | @ MIL | 88 | L 9-12 | 48-40 | 2 | 38,055 | Kevin Tapani | Jeff Juden | Alberto Reyes | Bob Patterson | Bob Wickman | 448 | 425 | 23 |
| 1998-07-10 | @ MIL | 89 | L 5-6 | 48-41 | 2 | 43,575 | Kerry Wood | Scott Karl | Bronswell Patrick | Kerry Wood | | 453 | 431 | 22 |
| 1998-07-11 | @ MIL | 90 | W 11-8 | 49-41 | 2 | 52,067 | Steve Trachsel | Cal Eldred | Steve Trachsel | Cal Eldred | Rod Beck | 464 | 439 | 25 |
| 1998-07-12 | @ MIL | 91 | W 3-0 | 50-41 | 2 | 50,735 | Mark Clark | Brad Woodall | Mark Clark | Brad Woodall | | 467 | 439 | 28 |
| 1998-07-13 | @ PIT | 92 | L 2-6 | 50-42 | 2 | 11,772 | Geremi Gonzalez | Jon Lieber | Jon Lieber | Geremi Gonzalez | | 469 | 445 | 24 |
| 1998-07-14 | @ PIT | 93 | W 7-4 | 51-42 | 2 | 13,405 | Kevin Tapani | Chris Peters | Kevin Tapani | Chris Peters | Rod Beck | 476 | 449 | 27 |
| 1998-07-15 | @ PIT | 94 | L 0-3 | 51-43 | 2 | 28,655 | Kerry Wood | Francisco Cordova | Francisco Cordova | Kerry Wood | Ricardo Rincon | 476 | 452 | 24 |
| 1998-07-17 | @ FLO | 95 | W 6-1 | 52-43 | 2 | 20,141 | Steve Trachsel | Ryan Dempster | Steve Trachsel | Ryan Dempster | | 482 | 453 | 29 |
| 1998-07-18 | @ FLO | 96 | L 1-2 | 52-44 | 2 | 32,062 | Mark Clark | Brian Meadows | Brian Meadows | Mark Clark | Matt Mantei | 483 | 455 | 28 |
| 1998-07-19 | @ FLO | 97 | W 7-6 | 53-44 | 2 | 20,866 | Geremi Gonzalez | Eric Ludwick | Terry Mulholland | Rob Stanifer | Rod Beck | 490 | 461 | 29 |
| 1998-07-20 | @ ATL | 98 | W 11-4 | 54-44 | 2 | 47,475 | Kevin Tapani | Denny Neagle | Kevin Tapani | Denny Neagle | | 501 | 465 | 36 |
| 1998-07-21 | @ ATL | 99 | W 3-0 | 55-44 | 2 | 47,933 | Kerry Wood | Greg Maddux | Kerry Wood | Greg Maddux | Rod Beck | 504 | 465 | 39 |
| 1998-07-22 | vs MON | 100 | W 9-5 | 56-44 | 2 | 39,179 | Steve Trachsel | Javier Vazquez | Terry Adams | Miguel Batista | Rod Beck | 513 | 470 | 43 |
| 1998-07-23 | vs MON | 101 | W 2-1 | 57-44 | 2 | 39,262 | Mark Clark | Jeremy Powell | Mark Clark | Jeremy Powell | Rod Beck | 515 | 471 | 44 |
| 1998-07-24 | vs NYN | 102 | L 0-5 | 57-46 | 2 | 0 | Geremi Gonzalez | Armando Reynoso | Armando Reynoso | Geremi Gonzalez | | 515 | 476 | 39 |
| 1998-07-24 | vs NYN | 103 | L 3-7 | 57-46 | 2 | 40,684 | Don Wengert | Bobby Jones | Dennis Cook | Terry Adams | | 518 | 483 | 35 |
| 1998-07-25 | vs NYN | 104 | W 3-2 | 58-46 | 2 | 40,436 | Kevin Tapani | Masato Yoshii | Kevin Tapani | John Franco | Rod Beck | 521 | 485 | 36 |
| 1998-07-26 | vs NYN | 105 | W 3-1 | 59-46 | 2 | 40,329 | Kerry Wood | Rick Reed | Kerry Wood | Rick Reed | Rod Beck | 524 | 486 | 38 |
| 1998-07-27 | @ ARI | 106 | W 6-2 | 60-46 | 2 | 46,373 | Steve Trachsel | Willie Blair | Steve Trachsel | Willie Blair | | 530 | 488 | 42 |
| 1998-07-28 | @ ARI | 107 | L 5-7 | 60-47 | 2 | 47,190 | Mark Clark | Bob Wolcott | Bob Wolcott | Mark Clark | Gregg Olson | 535 | 495 | 40 |
| 1998-07-29 | @ ARI | 108 | W 7-3 | 61-47 | 2 | 46,738 | Don Wengert | Amaury Telemaco | Don Wengert | Amaury Telemaco | Terry Adams | 542 | 498 | 44 |
| 1998-07-30 | @ ARI | 109 | L 0-4 | 61-48 | 2 | 46,728 | Kevin Tapani | Omar Daal | Omar Daal | Kevin Tapani | | 542 | 502 | 40 |
| 1998-07-31 | vs COL | 110 | W 9-1 | 62-48 | 2 | 40,490 | Kerry Wood | Jamey Wright | Kerry Wood | Jamey Wright | Terry Mulholland | 551 | 503 | 48 |
| 1998-08-01 | vs COL | 111 | W 3-2 | 63-48 | 2 | 40,198 | Steve Trachsel | John Thomson | Steve Trachsel | John Thomson | Rod Beck | 554 | 505 | 49 |
| 1998-08-02 | vs COL | 112 | L 3-6 | 63-49 | 2 | 39,427 | Mark Clark | Pedro Astacio | Pedro Astacio | Mark Clark | Chuck McElroy | 557 | 511 | 46 |
| 1998-08-03 | vs ARI | 113 | L 5-6 | 63-50 | 2 | 38,551 | Don Wengert | Amaury Telemaco | Amaury Telemaco | Don Wengert | Gregg Olson | 562 | 517 | 45 |
| 1998-08-04 | vs ARI | 114 | W 2-0 | 64-50 | 2 | 37,539 | Kevin Tapani | Omar Daal | Kevin Tapani | Omar Daal | Rod Beck | 564 | 517 | 47 |
| 1998-08-05 | vs ARI | 115 | L 7-10 | 64-51 | 2 | 39,664 | Kerry Wood | Andy Benes | Andy Benes | Kerry Wood | Gregg Olson | 571 | 527 | 44 |
| 1998-08-07 | @ SLN | 116 | L 3-16 | 64-52 | 2 | 47,911 | Steve Trachsel | Kent Bottenfield | Kent Bottenfield | Steve Trachsel | | 574 | 543 | 31 |
| 1998-08-08 | @ SLN | 117 | L 8-9 | 64-53 | 2 | 48,064 | Mark Clark | Donovan Osborne | Bobby Witt | Dave Stevens | | 582 | 552 | 30 |
| 1998-08-09 | @ SLN | 118 | L 1-2 | 64-54 | 2 | 47,798 | Don Wengert | Darren Oliver | Darren Oliver | Don Wengert | Jeff Brantley | 583 | 554 | 29 |
| 1998-08-10 | @ SFN | 119 | W 8-5 | 65-54 | 2 | 28,866 | Kevin Tapani | Russ Ortiz | Kevin Tapani | Russ Ortiz | Rod Beck | 591 | 559 | 32 |
| 1998-08-11 | @ SFN | 120 | L 7-8 | 65-55 | 2 | 25,065 | Kerry Wood | Orel Hershiser | Jose Mesa | Terry Adams | Robb Nen | 598 | 567 | 31 |
| 1998-08-12 | @ SFN | 121 | W 10-2 | 66-55 | 2 | 25,109 | Steve Trachsel | Kirk Rueter | Steve Trachsel | Kirk Rueter | | 608 | 569 | 39 |
| 1998-08-14 | @ HOU | 122 | W 6-4 | 67-55 | 2 | 45,040 | Mark Clark | Shane Reynolds | Mark Clark | Shane Reynolds | Rod Beck | 614 | 573 | 41 |
| 1998-08-15 | @ HOU | 123 | L 4-5 | 67-56 | 2 | 52,003 | Kevin Tapani | Mike Hampton | Billy Wagner | Terry Mulholland | | 618 | 578 | 40 |
| 1998-08-16 | @ HOU | 124 | W 2-1 | 68-56 | 2 | 52,199 | Kerry Wood | Sean Bergman | Matt Karchner | Jay Powell | Rod Beck | 620 | 579 | 41 |
| 1998-08-18 | vs SLN | 125 | W 4-1 | 69-56 | 2 | 40,249 | Steve Trachsel | Kent Mercker | Steve Trachsel | Kent Mercker | Rod Beck | 624 | 580 | 44 |
| 1998-08-19 | vs SLN | 126 | L 6-8 | 69-57 | 2 | 39,689 | Mark Clark | Kent Bottenfield | Juan Acevedo | Terry Mulholland | | 630 | 588 | 42 |
| 1998-08-20 | vs SFN | 127 | W 7-3 | 70-57 | 2 | 37,803 | Kevin Tapani | Russ Ortiz | Kevin Tapani | Russ Ortiz | | 637 | 591 | 46 |
| 1998-08-21 | vs SFN | 128 | W 6-5 | 71-57 | 2 | 39,059 | Kerry Wood | Orel Hershiser | Felix Heredia | Robb Nen | | 643 | 596 | 47 |
| 1998-08-22 | vs HOU | 129 | L 3-8 | 71-58 | 2 | 39,886 | Don Wengert | Randy Johnson | Randy Johnson | Don Wengert | | 646 | 604 | 42 |
| 1998-08-23 | vs HOU | 130 | L 3-13 | 71-59 | 2 | 38,714 | Steve Trachsel | Jose Lima | Jose Lima | Steve Trachsel | | 649 | 617 | 32 |
| 1998-08-24 | vs HOU | 131 | L 3-12 | 71-60 | 2 | 34,711 | Mark Clark | Shane Reynolds | Shane Reynolds | Mark Clark | | 652 | 629 | 23 |
| 1998-08-25 | @ CIN | 132 | L 9-10 | 71-61 | 2 | 20,828 | Kevin Tapani | Dennys Reyes | John Hudek | Terry Mulholland | Gabe White | 661 | 639 | 22 |
| 1998-08-26 | @ CIN | 133 | W 9-2 | 72-61 | 2 | 20,315 | Kerry Wood | Brett Tomko | Kerry Wood | Brett Tomko | | 670 | 641 | 29 |
| 1998-08-27 | @ COL | 134 | W 11-10 | 73-61 | 2 | 50,093 | Mike Morgan | Pedro Astacio | Terry Mulholland | Mike Munoz | Rod Beck | 681 | 651 | 30 |
| 1998-08-28 | @ COL | 135 | W 10-5 | 74-61 | 2 | 48,223 | Steve Trachsel | John Thomson | Steve Trachsel | John Thomson | | 691 | 656 | 35 |
| 1998-08-29 | @ COL | 136 | L 3-7 | 74-62 | 2 | 48,269 | Mark Clark | Bobby Jones | Bobby Jones | Mark Clark | | 694 | 663 | 31 |
| 1998-08-30 | @ COL | 137 | W 4-3 | 75-62 | 2 | 48,255 | Kevin Tapani | Darryl Kile | Kevin Tapani | Darryl Kile | Rod Beck | 698 | 666 | 32 |
| 1998-08-31 | vs CIN | 138 | W 5-4 | 76-62 | 2 | 36,700 | Kerry Wood | Brett Tomko | Kerry Wood | Brett Tomko | Rod Beck | 703 | 670 | 33 |
| 1998-09-01 | vs CIN | 139 | W 6-5 | 77-62 | 2 | 38,223 | Mike Morgan | Steve Parris | Matt Karchner | Gabe White | Rod Beck | 709 | 675 | 34 |
| 1998-09-02 | vs CIN | 140 | W 4-2 | 78-62 | 2 | 36,761 | Steve Trachsel | Jason Bere | Felix Heredia | Gabe White | Rod Beck | 713 | 677 | 36 |
| 1998-09-04 | @ PIT | 141 | W 5-2 | 79-62 | 2 | 36,510 | Mark Clark | Jason Schmidt | Matt Karchner | Mike Williams | Rod Beck | 718 | 679 | 39 |
| 1998-09-05 | @ PIT | 142 | W 8-4 | 80-62 | 2 | 37,711 | Kevin Tapani | Sean Lawrence | Kevin Tapani | Sean Lawrence | Rod Beck | 726 | 683 | 43 |
| 1998-09-06 | @ PIT | 143 | L 3-4 | 80-63 | 2 | 22,209 | Terry Mulholland | Chris Peters | Rich Loiselle | Dave Stevens | | 729 | 687 | 42 |
| 1998-09-07 | @ SLN | 144 | L 2-3 | 80-64 | 2 | 42,877 | Mike Morgan | Darren Oliver | Darren Oliver | Mike Morgan | Juan Acevedo | 731 | 690 | 41 |
| 1998-09-08 | @ SLN | 145 | L 3-6 | 80-65 | 2 | 43,688 | Steve Trachsel | Kent Mercker | Kent Mercker | Steve Trachsel | Juan Acevedo | 734 | 696 | 38 |
| 1998-09-09 | vs PIT | 146 | W 4-2 | 81-65 | 2 | 34,857 | Mark Clark | Jason Schmidt | Mark Clark | Jason Schmidt | Rod Beck | 738 | 698 | 40 |
| 1998-09-10 | vs PIT | 147 | W 5-2 | 82-65 | 2 | 38,722 | Kevin Tapani | Jose Silva | Kevin Tapani | Jose Silva | Rod Beck | 743 | 700 | 43 |
| 1998-09-11 | vs MIL | 148 | L 11-13 | 82-66 | 2 | 37,410 | Don Wengert | Bill Pulsipher | Eric Plunk | Don Wengert | Bob Wickman | 754 | 713 | 41 |
| 1998-09-12 | vs MIL | 149 | W 15-12 | 83-66 | 2 | 39,170 | Mike Morgan | Rafael Roque | Rod Beck | Bob Wickman | | 769 | 725 | 44 |
| 1998-09-13 | vs MIL | 150 | W 11-10 | 84-66 | 2 | 40,846 | Steve Trachsel | Brad Woodall | Rod Beck | Alberto Reyes | | 780 | 735 | 45 |
| 1998-09-14 | @ SDN | 151 | L 3-4 | 84-67 | 2 | 23,948 | Mark Clark | Sterling Hitchcock | Dan Miceli | Matt Karchner | Trevor Hoffman | 783 | 739 | 44 |
| 1998-09-15 | @ SDN | 152 | W 4-2 | 85-67 | 2 | 37,995 | Kevin Tapani | Kevin Brown | Kevin Tapani | Kevin Brown | Rod Beck | 787 | 741 | 46 |
| 1998-09-16 | @ SDN | 153 | W 6-3 | 86-67 | 2 | 49,981 | Terry Mulholland | Joey Hamilton | Terry Mulholland | Dan Miceli | Rod Beck | 793 | 744 | 49 |
| 1998-09-17 | @ SDN | 154 | W 4-3 | 87-67 | 2 | 32,047 | Mike Morgan | Stan Spencer | Felix Heredia | Trevor Hoffman | Rod Beck | 797 | 747 | 50 |
| 1998-09-18 | vs CIN | 155 | L 4-6 | 87-68 | 2 | 40,105 | Steve Trachsel | Steve Parris | Steve Parris | Don Wengert | Gabe White | 801 | 753 | 48 |
| 1998-09-19 | vs CIN | 156 | L 2-7 | 87-69 | 2 | 40,357 | Mark Clark | Jason Bere | Jason Bere | Mark Clark | | 803 | 760 | 43 |
| 1998-09-20 | vs CIN | 157 | L 3-7 | 87-70 | 2 | 40,117 | Kevin Tapani | Pete Harnisch | Pete Harnisch | Kevin Tapani | Gabe White | 806 | 767 | 39 |
| 1998-09-22 | @ MIL | 158 | W 5-2 | 88-70 | 2 | 52,287 | Terry Mulholland | Bill Pulsipher | Terry Mulholland | Bill Pulsipher | | 811 | 769 | 42 |
| 1998-09-23 | @ MIL | 159 | L 7-8 | 88-71 | 2 | 45,338 | Steve Trachsel | Rafael Roque | Chad Fox | Rod Beck | | 818 | 777 | 41 |
| 1998-09-25 | @ HOU | 160 | L 2-6 | 88-72 | 2 | 51,831 | Kevin Tapani | Jose Lima | Jose Lima | Kevin Tapani | | 820 | 783 | 37 |
| 1998-09-26 | @ HOU | 161 | W 3-2 | 89-72 | 2 | 51,950 | Mark Clark | Shane Reynolds | Mark Clark | Jay Powell | Rod Beck | 823 | 785 | 38 |
| 1998-09-27 | @ HOU | 162 | L 3-4 | 89-73 | 2 | 51,916 | Terry Mulholland | Mike Hampton | Scott Elarton | Rod Beck | | 826 | 789 | 37 |
| 1998-09-28 | vs SFN | 163 | W 5-3 | 90-73 | 2 | 39,556 | Steve Trachsel | Mark Gardner | Steve Trachsel | Mark Gardner | Rod Beck | 831 | 792 | 39 |