| 1988-04-05 | @ ATL | 1 | W 10-9 | 1-0 | 1 | 34,929 | Rick Sutcliffe | Rick Mahler | Mike Bielecki | Jim Acker | | 10 | 9 | 1 |
| 1988-04-06 | @ ATL | 2 | W 3-0 | 2-0 | 1 | 6,122 | Greg Maddux | Zane Smith | Greg Maddux | Zane Smith | | 13 | 9 | 4 |
| 1988-04-08 | @ MON | 3 | W 6-4 | 3-0 | 1 | 12,133 | Jamie Moyer | Floyd Youmans | Jamie Moyer | Floyd Youmans | Rich Gossage | 19 | 13 | 6 |
| 1988-04-09 | @ MON | 4 | L 6-10 | 3-1 | 1 | 11,806 | Calvin Schiraldi | Dennis Martinez | Dennis Martinez | Calvin Schiraldi | | 25 | 23 | 2 |
| 1988-04-10 | @ MON | 5 | W 10-7 | 4-1 | 1 | 15,704 | Rick Sutcliffe | Bryn Smith | Rich Gossage | Bob McClure | Les Lancaster | 35 | 30 | 5 |
| 1988-04-11 | @ SLN | 6 | W 6-1 | 5-1 | 1 | 32,275 | Greg Maddux | Bob Forsch | Greg Maddux | Bob Forsch | | 41 | 31 | 10 |
| 1988-04-12 | @ SLN | 7 | L 5-7 | 5-2 | 1 | 27,115 | Al Nipper | Jose DeLeon | Jose DeLeon | Drew Hall | Todd Worrell | 46 | 38 | 8 |
| 1988-04-13 | @ SLN | 8 | L 3-4 | 5-3 | 2 | 37,206 | Jamie Moyer | Danny Cox | Danny Cox | Les Lancaster | Todd Worrell | 49 | 42 | 7 |
| 1988-04-15 | vs PIT | 9 | W 6-0 | 6-3 | 1 | 35,084 | Rick Sutcliffe | John Smiley | Rick Sutcliffe | John Smiley | | 55 | 42 | 13 |
| 1988-04-16 | vs PIT | 10 | L 0-4 | 6-4 | 3 | 30,564 | Greg Maddux | Doug Drabek | Doug Drabek | Greg Maddux | | 55 | 46 | 9 |
| 1988-04-17 | vs PIT | 11 | L 7-12 | 6-5 | 3 | 29,562 | Calvin Schiraldi | Vicente Palacios | Jeff Robinson | Calvin Schiraldi | | 62 | 58 | 4 |
| 1988-04-19 | vs MON | 12 | L 1-9 | 6-6 | 3 | 7,293 | Jamie Moyer | Dennis Martinez | Dennis Martinez | Jamie Moyer | | 63 | 67 | -4 |
| 1988-04-20 | vs MON | 13 | L 1-5 | 6-7 | 4 | 5,699 | Rick Sutcliffe | Floyd Youmans | Jeff Parrett | Rick Sutcliffe | Tim Burke | 64 | 72 | -8 |
| 1988-04-21 | vs MON | 14 | W 6-2 | 7-7 | 3 | 6,625 | Greg Maddux | Bryn Smith | Greg Maddux | Bryn Smith | | 70 | 74 | -4 |
| 1988-04-22 | @ PIT | 15 | L 4-8 | 7-8 | 3 | 16,250 | Calvin Schiraldi | Doug Drabek | Doug Drabek | Les Lancaster | | 74 | 82 | -8 |
| 1988-04-23 | @ PIT | 16 | L 4-5 | 7-9 | 3 | 20,214 | Al Nipper | Brian Fisher | Jim Gott | Rich Gossage | | 78 | 87 | -9 |
| 1988-04-24 | @ PIT | 17 | L 2-4 | 7-10 | 4 | 19,934 | Rick Sutcliffe | Bob Walk | Bob Walk | Rick Sutcliffe | Jeff Robinson | 80 | 91 | -11 |
| 1988-04-26 | @ LAN | 18 | W 7-3 | 8-10 | 3 | 34,279 | Greg Maddux | Tim Leary | Greg Maddux | Tim Leary | | 87 | 94 | -7 |
| 1988-04-27 | @ LAN | 19 | L 0-4 | 8-11 | 4 | 29,462 | Jamie Moyer | Don Sutton | Don Sutton | Jamie Moyer | Alejandro Pena | 87 | 98 | -11 |
| 1988-04-28 | @ LAN | 20 | W 5-1 | 9-11 | 4 | 29,509 | Calvin Schiraldi | Tim Belcher | Calvin Schiraldi | Tim Belcher | Frank DiPino | 92 | 99 | -7 |
| 1988-04-29 | @ SFN | 21 | L 3-4 | 9-12 | 4 | 18,662 | Rick Sutcliffe | Mike Krukow | Atlee Hammaker | Rick Sutcliffe | Don Robinson | 95 | 103 | -8 |
| 1988-04-30 | @ SFN | 22 | W 2-1 | 10-12 | 3 | 32,405 | Al Nipper | Mike LaCoss | Les Lancaster | Joe Price | Rich Gossage | 97 | 104 | -7 |
| 1988-05-01 | @ SFN | 23 | L 6-7 | 10-13 | 4 | 30,658 | Greg Maddux | Rick Reuschel | Rick Reuschel | Greg Maddux | Atlee Hammaker | 103 | 111 | -8 |
| 1988-05-02 | @ SDN | 24 | W 5-2 | 11-13 | 3 | 21,435 | Jamie Moyer | Jimmy Jones | Jamie Moyer | Jimmy Jones | | 108 | 113 | -5 |
| 1988-05-03 | @ SDN | 25 | W 13-5 | 12-13 | 3 | 11,772 | Calvin Schiraldi | Ed Whitson | Calvin Schiraldi | Ed Whitson | | 121 | 118 | 3 |
| 1988-05-04 | @ SDN | 26 | W 6-3 | 13-13 | 3 | 12,662 | Rick Sutcliffe | Andy Hawkins | Rick Sutcliffe | Andy Hawkins | Rich Gossage | 127 | 121 | 6 |
| 1988-05-06 | vs SFN | 27 | W 3-2 | 14-13 | 3 | 29,709 | Greg Maddux | Mike LaCoss | Greg Maddux | Mike LaCoss | Rich Gossage | 130 | 123 | 7 |
| 1988-05-07 | vs SFN | 28 | L 1-2 | 14-14 | 3 | 32,596 | Jamie Moyer | Rick Reuschel | Rick Reuschel | Jamie Moyer | Don Robinson | 131 | 125 | 6 |
| 1988-05-08 | vs SFN | 29 | W 13-7 | 15-14 | 3 | 26,355 | Al Nipper | Joe Price | Mike Capel | Scott Garrelts | | 144 | 132 | 12 |
| 1988-05-10 | vs LAN | 30 | L 5-6 | 15-15 | 3 | 12,985 | Rick Sutcliffe | Tim Belcher | Brian Holton | Les Lancaster | Orel Hershiser | 149 | 138 | 11 |
| 1988-05-11 | vs SDN | 31 | W 1-0 | 16-15 | 3 | 12,600 | Greg Maddux | Mark Grant | Greg Maddux | Lance McCullers | | 150 | 138 | 12 |
| 1988-05-12 | vs SDN | 32 | W 2-1 | 17-15 | 3 | 15,638 | Calvin Schiraldi | Eric Show | Bill Landrum | Mark Davis | | 152 | 139 | 13 |
| 1988-05-13 | @ HOU | 33 | L 2-8 | 17-16 | 3 | 27,448 | Jamie Moyer | Nolan Ryan | Nolan Ryan | Jamie Moyer | | 154 | 147 | 7 |
| 1988-05-14 | @ HOU | 34 | L 1-3 | 17-17 | 3 | 33,894 | Al Nipper | Bob Knepper | Bob Knepper | Al Nipper | Dave Smith | 155 | 150 | 5 |
| 1988-05-15 | @ HOU | 35 | W 2-1 | 18-17 | 3 | 32,755 | Rick Sutcliffe | Danny Darwin | Rick Sutcliffe | Danny Darwin | | 157 | 151 | 6 |
| 1988-05-17 | vs SLN | 36 | L 0-3 | 18-18 | 3 | 21,762 | Greg Maddux | John Tudor | Scott Terry | Greg Maddux | Todd Worrell | 157 | 154 | 3 |
| 1988-05-18 | vs SLN | 37 | L 1-4 | 18-19 | 4 | 23,454 | Jamie Moyer | Jose DeLeon | Bob Forsch | Les Lancaster | Todd Worrell | 158 | 158 | 0 |
| 1988-05-19 | vs SLN | 38 | L 1-5 | 18-20 | 4 | 29,068 | Al Nipper | Cris Carpenter | Cris Carpenter | Al Nipper | | 159 | 163 | -4 |
| 1988-05-20 | @ CIN | 39 | L 2-7 | 18-21 | 4 | 36,356 | Rick Sutcliffe | Mario Soto | Mario Soto | Rick Sutcliffe | | 161 | 170 | -9 |
| 1988-05-21 | @ CIN | 40 | W 11-6 | 19-21 | 4 | 32,673 | Bob Tewksbury | Danny Jackson | Les Lancaster | Danny Jackson | | 172 | 176 | -4 |
| 1988-05-22 | @ CIN | 41 | W 5-1 | 20-21 | 4 | 33,185 | Greg Maddux | Tom Browning | Greg Maddux | Tom Browning | Frank DiPino | 177 | 177 | 0 |
| 1988-05-24 | vs ATL | 42 | L 0-3 | 21-22 | 4 | 0 | Jamie Moyer | Pete Smith | Jose Alvarez | Jamie Moyer | Bruce Sutter | 177 | 180 | -3 |
| 1988-05-24 | vs ATL | 43 | W 2-1 | 21-22 | 4 | 14,607 | Al Nipper | Charlie Puleo | Al Nipper | Charlie Puleo | Rich Gossage | 179 | 181 | -2 |
| 1988-05-25 | vs ATL | 44 | L 1-2 | 21-23 | 4 | 11,002 | Les Lancaster | Tom Glavine | Rick Mahler | Frank DiPino | Bruce Sutter | 180 | 183 | -3 |
| 1988-05-27 | vs HOU | 45 | W 3-2 | 22-23 | 4 | 22,958 | Greg Maddux | Danny Darwin | Greg Maddux | Danny Darwin | Rich Gossage | 183 | 185 | -2 |
| 1988-05-28 | vs HOU | 46 | W 14-7 | 23-23 | 4 | 34,690 | Calvin Schiraldi | Mike Scott | Calvin Schiraldi | Mike Scott | Frank DiPino | 197 | 192 | 5 |
| 1988-05-29 | vs HOU | 47 | L 1-7 | 23-24 | 4 | 35,356 | Jamie Moyer | Nolan Ryan | Nolan Ryan | Jamie Moyer | | 198 | 199 | -1 |
| 1988-05-30 | vs CIN | 48 | W 12-3 | 24-24 | 4 | 34,534 | Les Lancaster | Ron Robinson | Les Lancaster | Ron Robinson | | 210 | 202 | 8 |
| 1988-05-31 | vs CIN | 49 | W 4-0 | 25-24 | 4 | 19,038 | Jeff Pico | Mario Soto | Jeff Pico | Mario Soto | | 214 | 202 | 12 |
| 1988-06-01 | vs CIN | 50 | W 6-3 | 26-24 | 4 | 20,250 | Greg Maddux | Tom Browning | Greg Maddux | Tom Browning | | 220 | 205 | 15 |
| 1988-06-02 | @ NYN | 51 | L 1-2 | 26-25 | 4 | 29,578 | Calvin Schiraldi | David Cone | Randy Myers | Frank DiPino | | 221 | 207 | 14 |
| 1988-06-03 | @ NYN | 52 | W 5-0 | 27-25 | 4 | 40,516 | Jamie Moyer | Bob Ojeda | Jamie Moyer | Bob Ojeda | | 226 | 207 | 19 |
| 1988-06-04 | @ NYN | 53 | L 5-6 | 27-26 | 4 | 48,052 | Les Lancaster | Ron Darling | Jeff Innis | Mike Capel | | 231 | 213 | 18 |
| 1988-06-05 | @ NYN | 54 | L 3-11 | 27-27 | 4 | 47,243 | Jeff Pico | Dwight Gooden | Dwight Gooden | Jeff Pico | | 234 | 224 | 10 |
| 1988-06-07 | @ PIT | 55 | W 8-5 | 28-27 | 4 | 9,287 | Greg Maddux | Brian Fisher | Greg Maddux | Brian Fisher | Rich Gossage | 242 | 229 | 13 |
| 1988-06-08 | @ PIT | 56 | L 1-5 | 28-28 | 4 | 22,220 | Calvin Schiraldi | Bob Walk | Bob Walk | Calvin Schiraldi | | 243 | 234 | 9 |
| 1988-06-09 | @ PIT | 57 | L 3-4 | 28-29 | 4 | 8,200 | Jamie Moyer | John Smiley | Jim Gott | Frank DiPino | | 246 | 238 | 8 |
| 1988-06-10 | @ SLN | 58 | W 7-3 | 29-29 | 4 | 49,306 | Jeff Pico | Cris Carpenter | Jeff Pico | Cris Carpenter | | 253 | 241 | 12 |
| 1988-06-11 | @ SLN | 59 | W 2-0 | 30-29 | 4 | 49,939 | Rick Sutcliffe | Joe Magrane | Rick Sutcliffe | Joe Magrane | Rich Gossage | 255 | 241 | 14 |
| 1988-06-12 | @ SLN | 60 | W 4-3 | 31-29 | 4 | 48,713 | Greg Maddux | John Tudor | Greg Maddux | John Tudor | Pat Perry | 259 | 244 | 15 |
| 1988-06-13 | vs PIT | 61 | L 0-8 | 31-30 | 4 | 27,142 | Calvin Schiraldi | Bob Walk | Bob Walk | Calvin Schiraldi | | 259 | 252 | 7 |
| 1988-06-14 | vs PIT | 62 | L 3-6 | 31-31 | 4 | 28,077 | Jamie Moyer | John Smiley | John Smiley | Jamie Moyer | Jeff Robinson | 262 | 258 | 4 |
| 1988-06-15 | vs PIT | 63 | W 7-4 | 32-31 | 3 | 26,126 | Jeff Pico | Doug Drabek | Pat Perry | Jim Gott | Rich Gossage | 269 | 262 | 7 |
| 1988-06-17 | vs MON | 64 | W 7-3 | 33-31 | 3 | 33,041 | Rick Sutcliffe | Bryn Smith | Rick Sutcliffe | Bryn Smith | Les Lancaster | 276 | 265 | 11 |
| 1988-06-18 | vs MON | 65 | W 3-0 | 34-31 | 3 | 33,197 | Greg Maddux | John Dopson | Greg Maddux | John Dopson | | 279 | 265 | 14 |
| 1988-06-19 | vs MON | 66 | W 9-3 | 35-31 | 3 | 32,300 | Calvin Schiraldi | Dennis Martinez | Calvin Schiraldi | Dennis Martinez | | 288 | 268 | 20 |
| 1988-06-20 | @ PHI | 67 | W 7-2 | 36-31 | 3 | 26,616 | Jamie Moyer | Bruce Ruffin | Jamie Moyer | Bruce Ruffin | | 295 | 270 | 25 |
| 1988-06-21 | @ PHI | 68 | L 1-6 | 36-32 | 3 | 25,478 | Jeff Pico | David Palmer | David Palmer | Jeff Pico | | 296 | 276 | 20 |
| 1988-06-22 | @ PHI | 69 | L 3-5 | 36-33 | 3 | 27,322 | Rick Sutcliffe | Mike Maddux | Todd Frohwirth | Rick Sutcliffe | Steve Bedrosian | 299 | 281 | 18 |
| 1988-06-23 | vs NYN | 70 | W 4-1 | 37-33 | 3 | 32,771 | Greg Maddux | Sid Fernandez | Greg Maddux | Sid Fernandez | | 303 | 282 | 21 |
| 1988-06-24 | vs NYN | 71 | L 3-8 | 37-34 | 3 | 33,588 | Calvin Schiraldi | David Cone | David Cone | Calvin Schiraldi | Roger McDowell | 306 | 290 | 16 |
| 1988-06-25 | vs NYN | 72 | W 5-2 | 38-34 | 3 | 35,828 | Jamie Moyer | Bob Ojeda | Les Lancaster | Rick Aguilera | | 311 | 292 | 19 |
| 1988-06-26 | vs NYN | 73 | W 6-3 | 39-34 | 3 | 36,009 | Jeff Pico | Ron Darling | Jeff Pico | Ron Darling | | 317 | 295 | 22 |
| 1988-06-27 | vs PHI | 74 | W 2-1 | 40-34 | 3 | 27,945 | Rick Sutcliffe | Shane Rawley | Rick Sutcliffe | Shane Rawley | Al Nipper | 319 | 296 | 23 |
| 1988-06-28 | vs PHI | 75 | W 6-4 | 41-34 | 3 | 32,271 | Greg Maddux | Don Carman | Mike Capel | Steve Bedrosian | Les Lancaster | 325 | 300 | 25 |
| 1988-06-29 | vs PHI | 76 | L 2-4 | 41-35 | 3 | 30,812 | Calvin Schiraldi | Mike Maddux | Mike Maddux | Calvin Schiraldi | Steve Bedrosian | 327 | 304 | 23 |
| 1988-07-01 | @ LAN | 77 | W 9-2 | 42-35 | 3 | 42,763 | Jamie Moyer | Fernando Valenzuela | Jamie Moyer | Fernando Valenzuela | | 336 | 306 | 30 |
| 1988-07-02 | @ LAN | 78 | L 1-8 | 42-36 | 3 | 44,166 | Jeff Pico | Tim Leary | Tim Leary | Jeff Pico | | 337 | 314 | 23 |
| 1988-07-03 | @ LAN | 79 | W 2-1 | 43-36 | 3 | 43,209 | Rick Sutcliffe | Shawn Hillegas | Rick Sutcliffe | Shawn Hillegas | Les Lancaster | 339 | 315 | 24 |
| 1988-07-04 | @ SFN | 80 | W 3-2 | 44-36 | 2 | 22,076 | Greg Maddux | Don Robinson | Greg Maddux | Atlee Hammaker | | 342 | 317 | 25 |
| 1988-07-05 | @ SFN | 81 | L 0-9 | 44-37 | 3 | 13,786 | Calvin Schiraldi | Terry Mulholland | Terry Mulholland | Calvin Schiraldi | | 342 | 326 | 16 |
| 1988-07-06 | @ SFN | 82 | L 0-2 | 44-38 | 3 | 21,884 | Jamie Moyer | Rick Reuschel | Rick Reuschel | Jamie Moyer | Scott Garrelts | 342 | 328 | 14 |
| 1988-07-08 | @ SDN | 83 | L 2-4 | 44-39 | 3 | 19,071 | Jeff Pico | Dennis Rasmussen | Dennis Rasmussen | Jeff Pico | | 344 | 332 | 12 |
| 1988-07-09 | @ SDN | 84 | L 2-4 | 44-40 | 3 | 28,364 | Rick Sutcliffe | Ed Whitson | Ed Whitson | Rick Sutcliffe | Mark Davis | 346 | 336 | 10 |
| 1988-07-10 | @ SDN | 85 | W 4-2 | 45-40 | 3 | 19,835 | Greg Maddux | Eric Show | Greg Maddux | Eric Show | | 350 | 338 | 12 |
| 1988-07-14 | vs LAN | 86 | L 0-1 | 45-42 | 4 | 0 | Rick Sutcliffe | Tim Leary | Tim Leary | Rick Sutcliffe | Alejandro Pena | 350 | 339 | 11 |
| 1988-07-14 | vs LAN | 87 | L 3-6 | 45-42 | 4 | 34,031 | Calvin Schiraldi | Shawn Hillegas | Brian Holton | Calvin Schiraldi | Jay Howell | 353 | 345 | 8 |
| 1988-07-15 | vs LAN | 88 | L 2-3 | 45-43 | 4 | 32,179 | Greg Maddux | Fernando Valenzuela | Alejandro Pena | Al Nipper | Jesse Orosco | 355 | 348 | 7 |
| 1988-07-16 | vs LAN | 89 | W 2-2 | 46-43 | 4 | 32,843 | Jamie Moyer | Orel Hershiser | | | | 357 | 350 | 7 |
| 1988-07-17 | vs LAN | 90 | L 1-4 | 46-45 | 4 | 0 | Jeff Pico | Tim Belcher | Tim Belcher | Jeff Pico | Alejandro Pena | 358 | 354 | 4 |
| 1988-07-17 | vs LAN | 91 | L 2-5 | 46-45 | 4 | 35,138 | Al Nipper | Shawn Hillegas | Brian Holton | Les Lancaster | Jay Howell | 360 | 359 | 1 |
| 1988-07-18 | vs SFN | 92 | W 8-3 | 47-45 | 3 | 19,289 | Calvin Schiraldi | Don Robinson | Pat Perry | Craig Lefferts | | 368 | 362 | 6 |
| 1988-07-19 | vs SFN | 93 | L 1-3 | 47-46 | 3 | 33,712 | Rick Sutcliffe | Rick Reuschel | Rick Reuschel | Rick Sutcliffe | Scott Garrelts | 369 | 365 | 4 |
| 1988-07-20 | vs SFN | 94 | L 2-12 | 47-47 | 3 | 33,885 | Greg Maddux | Kelly Downs | Kelly Downs | Greg Maddux | | 371 | 377 | -6 |
| 1988-07-21 | vs SDN | 95 | L 1-3 | 47-48 | 4 | 28,485 | Jamie Moyer | Ed Whitson | Ed Whitson | Jamie Moyer | Lance McCullers | 372 | 380 | -8 |
| 1988-07-22 | vs SDN | 96 | W 5-4 | 48-48 | 3 | 30,903 | Al Nipper | Eric Show | Frank DiPino | Lance McCullers | | 377 | 384 | -7 |
| 1988-07-23 | vs SDN | 97 | W 3-2 | 49-48 | 3 | 33,007 | Calvin Schiraldi | Andy Hawkins | Calvin Schiraldi | Mark Grant | Rich Gossage | 380 | 386 | -6 |
| 1988-07-24 | vs SDN | 98 | L 1-2 | 49-49 | 4 | 33,217 | Rick Sutcliffe | Jimmy Jones | Jimmy Jones | Rick Sutcliffe | Mark Davis | 381 | 388 | -7 |
| 1988-07-26 | @ MON | 99 | L 4-8 | 49-50 | 4 | 26,029 | Greg Maddux | Dennis Martinez | Neal Heaton | Jeff Pico | | 385 | 396 | -11 |
| 1988-07-27 | @ MON | 100 | L 4-5 | 49-51 | 4 | 18,227 | Jamie Moyer | Brian Holman | Joe Hesketh | Pat Perry | | 389 | 401 | -12 |
| 1988-07-28 | @ PHI | 101 | W 7-0 | 50-51 | 4 | 23,767 | Calvin Schiraldi | Shane Rawley | Calvin Schiraldi | Shane Rawley | | 396 | 401 | -5 |
| 1988-07-29 | @ PHI | 102 | W 8-3 | 51-51 | 4 | 25,118 | Rick Sutcliffe | Kevin Gross | Rick Sutcliffe | Kevin Gross | | 404 | 404 | 0 |
| 1988-07-30 | @ PHI | 103 | L 2-3 | 51-52 | 4 | 24,625 | Al Nipper | Don Carman | Don Carman | Al Nipper | Steve Bedrosian | 406 | 407 | -1 |
| 1988-07-31 | @ PHI | 104 | L 3-6 | 51-53 | 4 | 35,066 | Greg Maddux | Mike Maddux | Mike Maddux | Greg Maddux | Bruce Ruffin | 409 | 413 | -4 |
| 1988-08-02 | @ NYN | 105 | L 1-3 | 51-54 | 4 | 45,916 | Jamie Moyer | David Cone | David Cone | Jamie Moyer | | 410 | 416 | -6 |
| 1988-08-03 | @ NYN | 106 | W 3-1 | 52-54 | 4 | 41,004 | Rick Sutcliffe | Bob Ojeda | Rick Sutcliffe | Bob Ojeda | | 413 | 417 | -4 |
| 1988-08-04 | @ NYN | 107 | W 4-3 | 53-54 | 4 | 41,978 | Calvin Schiraldi | Sid Fernandez | Calvin Schiraldi | Sid Fernandez | Frank DiPino | 417 | 420 | -3 |
| 1988-08-05 | vs PHI | 108 | L 3-9 | 53-55 | 4 | 28,801 | Greg Maddux | Don Carman | Don Carman | Greg Maddux | | 420 | 429 | -9 |
| 1988-08-06 | vs PHI | 109 | W 7-4 | 54-55 | 4 | 32,057 | Al Nipper | Mike Maddux | Al Nipper | Mike Maddux | Rich Gossage | 427 | 433 | -6 |
| 1988-08-07 | vs PHI | 110 | L 4-7 | 54-56 | 4 | 31,350 | Jamie Moyer | David Palmer | David Palmer | Jamie Moyer | Steve Bedrosian | 431 | 440 | -9 |
| 1988-08-09 | vs NYN | 111 | W 6-4 | 55-56 | 4 | 36,399 | Mike Bielecki | Sid Fernandez | Frank DiPino | Sid Fernandez | Rich Gossage | 437 | 444 | -7 |
| 1988-08-10 | vs NYN | 112 | W 6-5 | 56-56 | 4 | 29,422 | Greg Maddux | Ron Darling | Greg Maddux | Ron Darling | Frank DiPino | 443 | 449 | -6 |
| 1988-08-11 | vs NYN | 113 | L 6-9 | 56-57 | 4 | 31,942 | Al Nipper | Dwight Gooden | Terry Leach | Pat Perry | Roger McDowell | 449 | 458 | -9 |
| 1988-08-12 | vs SLN | 114 | L 0-4 | 56-58 | 4 | 31,596 | Rick Sutcliffe | Joe Magrane | Joe Magrane | Rick Sutcliffe | | 449 | 462 | -13 |
| 1988-08-13 | vs SLN | 115 | W 5-1 | 57-58 | 4 | 34,696 | Jamie Moyer | Bob Forsch | Jamie Moyer | Bob Forsch | | 454 | 463 | -9 |
| 1988-08-14 | vs SLN | 116 | W 8-3 | 58-58 | 4 | 32,016 | Mike Bielecki | Jose DeLeon | Mike Bielecki | Ken Dayley | Les Lancaster | 462 | 466 | -4 |
| 1988-08-16 | @ CIN | 117 | L 4-6 | 58-59 | 4 | 26,852 | Jeff Pico | Tom Browning | Frank Williams | Les Lancaster | John Franco | 466 | 472 | -6 |
| 1988-08-17 | @ CIN | 118 | W 5-0 | 59-59 | 4 | 26,505 | Rick Sutcliffe | Jack Armstrong | Rick Sutcliffe | Jack Armstrong | | 471 | 472 | -1 |
| 1988-08-18 | @ CIN | 119 | L 1-9 | 59-60 | 4 | 27,163 | Jamie Moyer | Danny Jackson | Danny Jackson | Jamie Moyer | | 472 | 481 | -9 |
| 1988-08-19 | vs ATL | 120 | W 8-7 | 60-60 | 4 | 27,912 | Greg Maddux | Rick Mahler | Rich Gossage | Jose Alvarez | | 480 | 488 | -8 |
| 1988-08-20 | vs ATL | 121 | W 5-4 | 61-60 | 4 | 33,325 | Calvin Schiraldi | Zane Smith | Drew Hall | Jim Acker | Jeff Pico | 485 | 492 | -7 |
| 1988-08-21 | vs ATL | 122 | L 0-1 | 61-61 | 4 | 33,097 | Mike Bielecki | Pete Smith | Pete Smith | Mike Bielecki | | 485 | 493 | -8 |
| 1988-08-22 | vs HOU | 123 | L 7-9 | 61-62 | 4 | 30,417 | Rick Sutcliffe | Mike Scott | Juan Agosto | Rich Gossage | | 492 | 502 | -10 |
| 1988-08-23 | vs HOU | 124 | W 9-3 | 62-62 | 4 | 34,668 | Jamie Moyer | Danny Darwin | Jamie Moyer | Danny Darwin | | 501 | 505 | -4 |
| 1988-08-24 | vs HOU | 125 | W 3-2 | 63-62 | 4 | 35,065 | Greg Maddux | Nolan Ryan | Jeff Pico | Juan Agosto | | 504 | 507 | -3 |
| 1988-08-25 | @ ATL | 126 | W 6-1 | 64-62 | 4 | 7,882 | Calvin Schiraldi | German Jimenez | Calvin Schiraldi | German Jimenez | | 510 | 508 | 2 |
| 1988-08-26 | @ ATL | 127 | L 0-4 | 64-63 | 4 | 19,173 | Rick Sutcliffe | Pete Smith | Pete Smith | Rick Sutcliffe | | 510 | 512 | -2 |
| 1988-08-27 | @ ATL | 128 | W 5-0 | 65-63 | 4 | 20,256 | Jeff Pico | Tom Glavine | Jeff Pico | Tom Glavine | | 515 | 512 | 3 |
| 1988-08-28 | @ ATL | 129 | L 2-4 | 65-64 | 4 | 17,377 | Jamie Moyer | John Smoltz | John Smoltz | Jamie Moyer | Paul Assenmacher | 517 | 516 | 1 |
| 1988-08-29 | @ HOU | 130 | W 2-1 | 66-64 | 3 | 23,142 | Greg Maddux | Nolan Ryan | Scott Sanderson | Larry Andersen | Drew Hall | 519 | 517 | 2 |
| 1988-08-30 | @ HOU | 131 | L 4-7 | 66-65 | 3 | 17,053 | Calvin Schiraldi | Joaquin Andujar | Joaquin Andujar | Calvin Schiraldi | Dave Smith | 523 | 524 | -1 |
| 1988-08-31 | @ HOU | 132 | W 3-1 | 67-65 | 3 | 14,200 | Rick Sutcliffe | Jim Deshaies | Rick Sutcliffe | Jim Deshaies | | 526 | 525 | 1 |
| 1988-09-02 | vs CIN | 133 | L 5-6 | 67-66 | 4 | 21,751 | Jeff Pico | Tom Browning | Tom Browning | Jeff Pico | John Franco | 531 | 531 | 0 |
| 1988-09-03 | vs CIN | 134 | L 4-6 | 67-67 | 4 | 33,087 | Greg Maddux | Jack Armstrong | Jack Armstrong | Greg Maddux | John Franco | 535 | 537 | -2 |
| 1988-09-04 | vs CIN | 135 | L 0-17 | 67-68 | 4 | 27,853 | Calvin Schiraldi | Danny Jackson | Danny Jackson | Calvin Schiraldi | | 535 | 554 | -19 |
| 1988-09-05 | vs PHI | 136 | W 14-3 | 68-69 | 4 | 0 | Rick Sutcliffe | Bob Sebra | Rick Sutcliffe | Bob Sebra | | 549 | 557 | -8 |
| 1988-09-05 | vs PHI | 137 | L 3-4 | 68-69 | 4 | 27,084 | Mike Harkey | Shane Rawley | Shane Rawley | Scott Sanderson | Steve Bedrosian | 552 | 561 | -9 |
| 1988-09-06 | vs PHI | 138 | L 2-3 | 68-70 | 4 | 23,189 | Jamie Moyer | Marvin Freeman | Marvin Freeman | Jamie Moyer | Steve Bedrosian | 554 | 564 | -10 |
| 1988-09-07 | vs NYN | 139 | W 9-8 | 69-70 | 4 | 32,297 | Jeff Pico | Ron Darling | Rich Gossage | Roger McDowell | | 563 | 572 | -9 |
| 1988-09-08 | vs NYN | 140 | L 6-13 | 69-71 | 4 | 16,644 | Greg Maddux | Dwight Gooden | Dwight Gooden | Scott Sanderson | | 569 | 585 | -16 |
| 1988-09-09 | @ SLN | 141 | L 2-6 | 69-72 | 4 | 38,991 | Calvin Schiraldi | Greg Mathews | Greg Mathews | Calvin Schiraldi | Todd Worrell | 571 | 591 | -20 |
| 1988-09-10 | @ SLN | 142 | L 3-9 | 69-73 | 4 | 41,151 | Rick Sutcliffe | Scott Terry | Scott Terry | Rick Sutcliffe | | 574 | 600 | -26 |
| 1988-09-11 | @ SLN | 143 | L 2-3 | 69-74 | 5 | 39,440 | Mike Harkey | Jose DeLeon | Jose DeLeon | Mike Harkey | Ken Dayley | 576 | 603 | -27 |
| 1988-09-12 | @ PHI | 144 | L 1-5 | 69-75 | 5 | 13,433 | Jamie Moyer | Don Carman | Don Carman | Jamie Moyer | Kent Tekulve | 577 | 608 | -31 |
| 1988-09-13 | @ PHI | 145 | W 9-2 | 70-75 | 4 | 13,301 | Greg Maddux | Kevin Gross | Greg Maddux | Kevin Gross | | 586 | 610 | -24 |
| 1988-09-14 | @ NYN | 146 | L 1-3 | 70-76 | 4 | 38,382 | Calvin Schiraldi | Sid Fernandez | Sid Fernandez | Calvin Schiraldi | Roger McDowell | 587 | 613 | -26 |
| 1988-09-15 | @ NYN | 147 | L 1-4 | 70-77 | 5 | 20,857 | Rick Sutcliffe | David Cone | David Cone | Rick Sutcliffe | Terry Leach | 588 | 617 | -29 |
| 1988-09-16 | vs SLN | 148 | L 0-3 | 70-78 | 5 | 15,771 | Mike Harkey | Jose DeLeon | Jose DeLeon | Mike Harkey | Todd Worrell | 588 | 620 | -32 |
| 1988-09-17 | vs SLN | 149 | W 6-4 | 71-78 | 5 | 30,243 | Jamie Moyer | Joe Magrane | Jeff Pico | John Costello | | 594 | 624 | -30 |
| 1988-09-18 | vs SLN | 150 | L 4-5 | 71-79 | 5 | 25,090 | Greg Maddux | Larry McWilliams | Larry McWilliams | Greg Maddux | Todd Worrell | 598 | 629 | -31 |
| 1988-09-20 | vs MON | 151 | W 5-4 | 72-80 | 5 | 0 | Rick Sutcliffe | Dennis Martinez | Rick Sutcliffe | Tim Burke | | 603 | 633 | -30 |
| 1988-09-20 | vs MON | 152 | L 1-9 | 72-80 | 5 | 23,030 | Calvin Schiraldi | Randy Johnson | Randy Johnson | Calvin Schiraldi | | 604 | 642 | -38 |
| 1988-09-21 | vs MON | 153 | L 5-8 | 72-81 | 5 | 8,360 | Mike Harkey | John Dopson | Joe Hesketh | Rich Gossage | Tim Burke | 609 | 650 | -41 |
| 1988-09-23 | @ PIT | 154 | W 5-3 | 73-81 | 5 | 19,552 | Greg Maddux | Doug Drabek | Jamie Moyer | Bob Kipper | | 614 | 653 | -39 |
| 1988-09-24 | @ PIT | 155 | W 2-1 | 74-81 | 4 | 16,161 | Mike Bielecki | Bob Walk | Rich Gossage | Dave Rucker | Frank DiPino | 616 | 654 | -38 |
| 1988-09-25 | @ PIT | 156 | L 4-7 | 74-82 | 4 | 23,095 | Rick Sutcliffe | Mike Dunne | Randy Kramer | Rick Sutcliffe | Jim Gott | 620 | 661 | -41 |
| 1988-09-26 | @ MON | 157 | L 2-3 | 74-83 | 5 | 6,577 | Mike Harkey | Randy Johnson | Randy Johnson | Mike Harkey | Tim Burke | 622 | 664 | -42 |
| 1988-09-27 | @ MON | 158 | W 5-3 | 75-83 | 4 | 6,131 | Calvin Schiraldi | Brian Holman | Calvin Schiraldi | Brian Holman | Rich Gossage | 627 | 667 | -40 |
| 1988-09-28 | @ MON | 159 | W 3-1 | 76-83 | 4 | 5,678 | Greg Maddux | John Dopson | Greg Maddux | John Dopson | | 630 | 668 | -38 |
| 1988-09-29 | @ MON | 160 | L 4-5 | 76-84 | 5 | 6,300 | Mike Bielecki | Bryn Smith | Bryn Smith | Mike Bielecki | Tim Burke | 634 | 673 | -39 |
| 1988-09-30 | vs PIT | 161 | L 9-10 | 76-85 | 5 | 9,805 | Rick Sutcliffe | Mike Dunne | Scott Medvin | Rich Gossage | Brian Fisher | 643 | 683 | -40 |
| 1988-10-01 | vs PIT | 162 | W 9-7 | 77-85 | 4 | 21,433 | Kevin Blankenship | Randy Kramer | Kevin Blankenship | Randy Kramer | Calvin Schiraldi | 652 | 690 | -38 |
| 1988-10-02 | vs PIT | 163 | W 8-4 | 78-85 | 4 | 22,909 | Jamie Moyer | John Smiley | Jamie Moyer | John Smiley | | 660 | 694 | -34 |