| 1988-04-05 | vs SDN | 1 | W 6-3 | - | | 39,906 | Mike Scott | Ed Whitson | Mike Scott | Lance McCullers | Dave Smith | 6 | 3 | 3 |
| 1988-04-06 | vs SDN | 2 | W 5-1 | - | | 14,865 | Bob Knepper | Andy Hawkins | Bob Knepper | Andy Hawkins | | 11 | 4 | 7 |
| 1988-04-08 | @ CIN | 3 | W 8-3 | - | | 32,286 | Nolan Ryan | Tom Browning | Larry Andersen | Jose Rijo | | 19 | 7 | 12 |
| 1988-04-09 | @ CIN | 4 | L 4-5 | - | | 25,615 | Danny Darwin | Dennis Rasmussen | Jose Rijo | Dave Smith | | 23 | 12 | 11 |
| 1988-04-10 | @ CIN | 5 | W 12-3 | - | | 29,954 | Mike Scott | Ron Robinson | Mike Scott | Ron Robinson | | 35 | 15 | 20 |
| 1988-04-12 | @ ATL | 6 | W 8-3 | - | | 1,938 | Nolan Ryan | Zane Smith | Nolan Ryan | Zane Smith | | 43 | 18 | 25 |
| 1988-04-13 | @ ATL | 7 | W 4-0 | - | | 3,810 | Jim Deshaies | Pete Smith | Jim Deshaies | Pete Smith | | 47 | 18 | 29 |
| 1988-04-14 | vs CIN | 8 | W 9-3 | - | | 17,835 | Danny Darwin | Dennis Rasmussen | Danny Darwin | Dennis Rasmussen | | 56 | 21 | 35 |
| 1988-04-15 | vs CIN | 9 | L 2-4 | - | | 32,417 | Mike Scott | Ron Robinson | Jose Rijo | Larry Andersen | John Franco | 58 | 25 | 33 |
| 1988-04-16 | vs CIN | 10 | L 2-8 | - | | 21,308 | Bob Knepper | Mario Soto | Jose Rijo | Ernie Camacho | | 60 | 33 | 27 |
| 1988-04-17 | vs CIN | 11 | W 5-3 | - | | 32,586 | Nolan Ryan | Danny Jackson | Nolan Ryan | Danny Jackson | Dave Smith | 65 | 36 | 29 |
| 1988-04-19 | vs ATL | 12 | L 4-5 | - | | 13,131 | Jim Deshaies | Pete Smith | Bruce Sutter | Jim Deshaies | Paul Assenmacher | 69 | 41 | 28 |
| 1988-04-20 | vs ATL | 13 | W 1-0 | - | | 13,383 | Mike Scott | Tom Glavine | Mike Scott | Tom Glavine | | 70 | 41 | 29 |
| 1988-04-21 | vs ATL | 14 | W 8-0 | - | | 12,491 | Bob Knepper | Kevin Coffman | Bob Knepper | Kevin Coffman | Ernie Camacho | 78 | 41 | 37 |
| 1988-04-22 | @ SDN | 15 | L 1-3 | - | | 35,695 | Nolan Ryan | Jimmy Jones | Jimmy Jones | Nolan Ryan | Mark Davis | 79 | 44 | 35 |
| 1988-04-23 | @ SDN | 16 | L 0-4 | - | | 11,104 | Danny Darwin | Ed Whitson | Ed Whitson | Danny Darwin | | 79 | 48 | 31 |
| 1988-04-24 | @ SDN | 17 | L 0-3 | - | | 15,976 | Jim Deshaies | Andy Hawkins | Andy Hawkins | Jim Deshaies | | 79 | 51 | 28 |
| 1988-04-26 | vs PHI | 18 | W 3-1 | - | | 13,152 | Mike Scott | Shane Rawley | Mike Scott | Shane Rawley | Dave Smith | 82 | 52 | 30 |
| 1988-04-27 | vs PHI | 19 | W 3-2 | - | | 14,462 | Nolan Ryan | Kevin Gross | Dave Smith | Kent Tekulve | | 85 | 54 | 31 |
| 1988-04-29 | vs MON | 20 | W 6-4 | - | | 34,331 | Danny Darwin | Dennis Martinez | Juan Agosto | Tim Burke | Dave Smith | 91 | 58 | 33 |
| 1988-04-30 | vs MON | 21 | W 3-0 | - | | 30,384 | Jim Deshaies | Bryn Smith | Jim Deshaies | Bryn Smith | Dave Smith | 94 | 58 | 36 |
| 1988-05-01 | vs MON | 22 | L 3-7 | - | | 26,231 | Mike Scott | Neal Heaton | Jeff Parrett | Jeff Heathcock | | 97 | 65 | 32 |
| 1988-05-02 | @ PHI | 23 | L 1-7 | - | | 18,931 | Nolan Ryan | Kevin Gross | Kevin Gross | Nolan Ryan | | 98 | 72 | 26 |
| 1988-05-03 | @ PHI | 24 | W 4-0 | - | | 16,443 | Bob Knepper | Bruce Ruffin | Bob Knepper | Bruce Ruffin | | 102 | 72 | 30 |
| 1988-05-04 | @ NYN | 25 | L 0-8 | - | | 29,936 | Danny Darwin | Sid Fernandez | Sid Fernandez | Danny Darwin | Terry Leach | 102 | 80 | 22 |
| 1988-05-06 | @ MON | 26 | L 5-6 | - | | 16,572 | Mike Scott | Neal Heaton | Bob McClure | Ernie Camacho | | 107 | 86 | 21 |
| 1988-05-07 | @ MON | 27 | L 3-4 | - | | 12,661 | Nolan Ryan | Pascual Perez | Jeff Parrett | Jeff Heathcock | | 110 | 90 | 20 |
| 1988-05-08 | @ MON | 28 | W 7-2 | - | | 14,873 | Bob Knepper | Floyd Youmans | Bob Knepper | Floyd Youmans | | 117 | 92 | 25 |
| 1988-05-09 | vs NYN | 29 | W 6-2 | - | | 18,388 | Danny Darwin | Sid Fernandez | Danny Darwin | Sid Fernandez | | 123 | 94 | 29 |
| 1988-05-10 | vs NYN | 30 | L 2-5 | - | | 19,064 | Jim Deshaies | David Cone | David Cone | Ernie Camacho | Roger McDowell | 125 | 99 | 26 |
| 1988-05-11 | vs NYN | 31 | L 8-9 | - | | 29,565 | Mike Scott | Dwight Gooden | Terry Leach | Dave Smith | | 133 | 108 | 25 |
| 1988-05-13 | vs CHN | 32 | W 8-2 | - | | 27,448 | Nolan Ryan | Jamie Moyer | Nolan Ryan | Jamie Moyer | | 141 | 110 | 31 |
| 1988-05-14 | vs CHN | 33 | W 3-1 | - | | 33,894 | Bob Knepper | Al Nipper | Bob Knepper | Al Nipper | Dave Smith | 144 | 111 | 33 |
| 1988-05-15 | vs CHN | 34 | L 1-2 | - | | 32,755 | Danny Darwin | Rick Sutcliffe | Rick Sutcliffe | Danny Darwin | | 145 | 113 | 32 |
| 1988-05-16 | vs PIT | 35 | W 9-2 | - | | 13,570 | Jim Deshaies | Bob Walk | Jim Deshaies | Bob Walk | | 154 | 115 | 39 |
| 1988-05-17 | vs PIT | 36 | W 3-2 | - | | 15,000 | Mike Scott | John Smiley | Mike Scott | John Smiley | Dave Smith | 157 | 117 | 40 |
| 1988-05-18 | vs PIT | 37 | W 4-2 | - | | 19,259 | Nolan Ryan | Doug Drabek | Nolan Ryan | Doug Drabek | Dave Smith | 161 | 119 | 42 |
| 1988-05-20 | @ SLN | 38 | W 5-3 | - | | 48,787 | Bob Knepper | Larry McWilliams | Bob Knepper | Scott Terry | Dave Smith | 166 | 122 | 44 |
| 1988-05-21 | @ SLN | 39 | L 4-7 | - | | 47,320 | Danny Darwin | Randy O'Neal | Bob Forsch | Joaquin Andujar | | 170 | 129 | 41 |
| 1988-05-22 | @ SLN | 40 | W 2-1 | - | | 42,632 | Jim Deshaies | John Tudor | Juan Agosto | Ken Dayley | Larry Andersen | 172 | 130 | 42 |
| 1988-05-23 | @ PIT | 41 | W 3-0 | - | | 7,480 | Mike Scott | John Smiley | Mike Scott | John Smiley | | 175 | 130 | 45 |
| 1988-05-24 | @ PIT | 42 | L 4-5 | - | | 8,200 | Nolan Ryan | Doug Drabek | Jim Gott | Larry Andersen | | 179 | 135 | 44 |
| 1988-05-25 | @ PIT | 43 | L 3-4 | - | | 8,108 | Bob Knepper | Mike Dunne | Mike Dunne | Joaquin Andujar | Jeff Robinson | 182 | 139 | 43 |
| 1988-05-27 | @ CHN | 44 | L 2-3 | - | | 22,958 | Danny Darwin | Greg Maddux | Greg Maddux | Danny Darwin | Rich Gossage | 184 | 142 | 42 |
| 1988-05-28 | @ CHN | 45 | L 7-14 | - | | 34,690 | Mike Scott | Calvin Schiraldi | Calvin Schiraldi | Mike Scott | Frank DiPino | 191 | 156 | 35 |
| 1988-05-29 | @ CHN | 46 | W 7-1 | - | | 35,356 | Nolan Ryan | Jamie Moyer | Nolan Ryan | Jamie Moyer | | 198 | 157 | 41 |
| 1988-05-30 | vs SLN | 47 | W 5-4 | - | | 26,000 | Jim Deshaies | Cris Carpenter | Jim Deshaies | Scott Terry | Dave Smith | 203 | 161 | 42 |
| 1988-05-31 | vs SLN | 48 | L 7-9 | - | | 19,666 | Bob Knepper | Larry McWilliams | Larry McWilliams | Bob Knepper | Todd Worrell | 210 | 170 | 40 |
| 1988-06-01 | vs SLN | 49 | L 2-3 | - | | 20,833 | Danny Darwin | Randy O'Neal | Steve Peters | Jeff Heathcock | Todd Worrell | 212 | 173 | 39 |
| 1988-06-03 | @ SFN | 50 | W 8-4 | - | | 18,840 | Mike Scott | Mike Krukow | Dave Smith | Scott Garrelts | | 220 | 177 | 43 |
| 1988-06-04 | @ SFN | 51 | L 2-8 | - | | 24,031 | Nolan Ryan | Mike LaCoss | Mike LaCoss | Nolan Ryan | Joe Price | 222 | 185 | 37 |
| 1988-06-05 | @ SFN | 52 | L 3-9 | - | | 31,144 | Jim Deshaies | Rick Reuschel | Rick Reuschel | Jim Deshaies | Craig Lefferts | 225 | 194 | 31 |
| 1988-06-06 | @ LAN | 53 | W 10-4 | - | | 19,327 | Bob Knepper | Don Sutton | Bob Knepper | Alejandro Pena | Larry Andersen | 235 | 198 | 37 |
| 1988-06-07 | @ LAN | 54 | W 5-2 | - | | 25,509 | Danny Darwin | Tim Belcher | Danny Darwin | Tim Belcher | | 240 | 200 | 40 |
| 1988-06-08 | @ LAN | 55 | L 1-11 | - | | 33,737 | Mike Scott | Fernando Valenzuela | Fernando Valenzuela | Mike Scott | | 241 | 211 | 30 |
| 1988-06-09 | @ LAN | 56 | L 2-4 | - | | 25,959 | Nolan Ryan | Orel Hershiser | Orel Hershiser | Nolan Ryan | Jay Howell | 243 | 215 | 28 |
| 1988-06-10 | vs ATL | 57 | L 3-10 | - | | 35,601 | Jim Deshaies | Tom Glavine | Juan Eichelberger | Dave Smith | | 246 | 225 | 21 |
| 1988-06-11 | vs ATL | 58 | W 5-4 | - | | 32,459 | Bob Knepper | Zane Smith | Dave Smith | Charlie Puleo | | 251 | 229 | 22 |
| 1988-06-12 | vs ATL | 59 | W 5-0 | - | | 31,778 | Mike Scott | Rick Mahler | Mike Scott | Rick Mahler | | 256 | 229 | 27 |
| 1988-06-13 | vs ATL | 60 | W 6-5 | - | | 21,485 | Nolan Ryan | Kevin Coffman | Juan Agosto | Jose Alvarez | Dave Smith | 262 | 234 | 28 |
| 1988-06-14 | @ CIN | 61 | L 1-7 | - | | 25,681 | Danny Darwin | Jose Rijo | Jose Rijo | Danny Darwin | | 263 | 241 | 22 |
| 1988-06-15 | @ CIN | 62 | L 3-5 | - | | 23,461 | Jim Deshaies | Tom Browning | Tom Browning | Jim Deshaies | John Franco | 266 | 246 | 20 |
| 1988-06-16 | @ CIN | 63 | W 7-4 | - | | 22,614 | Mike Scott | Mario Soto | Mike Scott | Mario Soto | Dave Smith | 273 | 250 | 23 |
| 1988-06-17 | @ ATL | 64 | L 3-4 | - | | 0 | Bob Knepper | Rick Mahler | Paul Assenmacher | Larry Andersen | Bruce Sutter | 276 | 254 | 22 |
| 1988-06-17 | @ ATL | 65 | L 5-6 | - | | 12,878 | Joaquin Andujar | Charlie Puleo | Juan Eichelberger | Dave Smith | | 281 | 260 | 21 |
| 1988-06-18 | @ ATL | 66 | W 14-7 | - | | 17,437 | Nolan Ryan | Kevin Coffman | Juan Agosto | Paul Assenmacher | Larry Andersen | 295 | 267 | 28 |
| 1988-06-19 | @ ATL | 67 | W 6-4 | - | | 9,750 | Danny Darwin | Pete Smith | Rocky Childress | Bruce Sutter | Dave Smith | 301 | 271 | 30 |
| 1988-06-20 | vs CIN | 68 | L 1-2 | - | | 18,889 | Jim Deshaies | Tom Browning | Tom Browning | Jim Deshaies | John Franco | 302 | 273 | 29 |
| 1988-06-21 | vs CIN | 69 | W 3-1 | - | | 18,220 | Mike Scott | Jack Armstrong | Larry Andersen | Jack Armstrong | Dave Smith | 305 | 274 | 31 |
| 1988-06-22 | vs CIN | 70 | W 5-1 | - | | 20,677 | Bob Knepper | Danny Jackson | Juan Agosto | Danny Jackson | | 310 | 275 | 35 |
| 1988-06-24 | vs SFN | 71 | L 0-11 | - | | 35,141 | Nolan Ryan | Kelly Downs | Kelly Downs | Nolan Ryan | | 310 | 286 | 24 |
| 1988-06-25 | vs SFN | 72 | L 1-4 | - | | 33,218 | Danny Darwin | Mike Krukow | Mike Krukow | Danny Darwin | | 311 | 290 | 21 |
| 1988-06-26 | vs SFN | 73 | W 6-0 | - | | 25,754 | Jim Deshaies | Mike LaCoss | Jim Deshaies | Mike LaCoss | | 317 | 290 | 27 |
| 1988-06-27 | vs LAN | 74 | L 0-4 | - | | 27,185 | Joaquin Andujar | Shawn Hillegas | Shawn Hillegas | Joaquin Andujar | Alejandro Pena | 317 | 294 | 23 |
| 1988-06-28 | vs LAN | 75 | W 4-3 | - | | 28,838 | Bob Knepper | Don Sutton | Bob Knepper | Brian Holton | Juan Agosto | 321 | 297 | 24 |
| 1988-06-29 | vs LAN | 76 | L 0-2 | - | | 27,678 | Nolan Ryan | Orel Hershiser | Orel Hershiser | Nolan Ryan | | 321 | 299 | 22 |
| 1988-06-30 | @ NYN | 77 | L 6-12 | - | | 48,671 | Danny Darwin | Bob Ojeda | Bob Ojeda | Danny Darwin | Terry Leach | 327 | 311 | 16 |
| 1988-07-01 | @ NYN | 78 | L 2-3 | - | | 0 | Joaquin Andujar | Ron Darling | Ron Darling | Joaquin Andujar | Randy Myers | 329 | 314 | 15 |
| 1988-07-01 | @ NYN | 79 | W 6-5 | - | | 42,042 | Jim Deshaies | Rick Aguilera | Dave Meads | Gene Walter | | 335 | 319 | 16 |
| 1988-07-02 | @ NYN | 80 | L 2-7 | - | | 44,715 | Bob Knepper | Dwight Gooden | Dwight Gooden | Bob Knepper | | 337 | 326 | 11 |
| 1988-07-03 | @ NYN | 81 | L 0-5 | - | | 40,973 | Nolan Ryan | Sid Fernandez | Sid Fernandez | Nolan Ryan | | 337 | 331 | 6 |
| 1988-07-04 | vs MON | 82 | L 4-7 | - | | 15,130 | Danny Darwin | Dennis Martinez | Dennis Martinez | Danny Darwin | Jeff Parrett | 341 | 338 | 3 |
| 1988-07-05 | vs MON | 83 | L 3-4 | - | | 13,342 | Joaquin Andujar | Brian Holman | Jeff Parrett | Dave Smith | Neal Heaton | 344 | 342 | 2 |
| 1988-07-06 | vs MON | 84 | L 2-4 | - | | 13,553 | Jim Deshaies | Pascual Perez | Pascual Perez | Jim Deshaies | Joe Hesketh | 346 | 346 | 0 |
| 1988-07-08 | vs NYN | 85 | W 4-2 | - | | 34,803 | Bob Knepper | Dwight Gooden | Bob Knepper | Dwight Gooden | | 350 | 348 | 2 |
| 1988-07-09 | vs NYN | 86 | W 6-3 | - | | 36,652 | Nolan Ryan | Sid Fernandez | Nolan Ryan | Rick Aguilera | Juan Agosto | 356 | 351 | 5 |
| 1988-07-10 | vs NYN | 87 | W 6-5 | - | | 33,772 | Danny Darwin | David Cone | Juan Agosto | Roger McDowell | | 362 | 356 | 6 |
| 1988-07-14 | @ PHI | 88 | W 7-5 | - | | 24,302 | Mike Scott | Shane Rawley | Juan Agosto | Kent Tekulve | Dave Smith | 369 | 361 | 8 |
| 1988-07-15 | @ PHI | 89 | W 5-2 | - | | 26,545 | Jim Deshaies | Kevin Gross | Jim Deshaies | Kevin Gross | Danny Darwin | 374 | 363 | 11 |
| 1988-07-16 | @ PHI | 90 | L 6-10 | - | | 32,871 | Nolan Ryan | Don Carman | Bruce Ruffin | Danny Darwin | | 380 | 373 | 7 |
| 1988-07-17 | @ PHI | 91 | L 4-10 | - | | 28,149 | Bob Knepper | Mike Maddux | Kent Tekulve | Bob Knepper | | 384 | 383 | 1 |
| 1988-07-18 | @ MON | 92 | W 6-1 | - | | 17,390 | Joaquin Andujar | Bryn Smith | Joaquin Andujar | Bryn Smith | Danny Darwin | 390 | 384 | 6 |
| 1988-07-19 | @ MON | 93 | W 4-3 | - | | 30,757 | Mike Scott | Pascual Perez | Mike Scott | Pascual Perez | Dave Smith | 394 | 387 | 7 |
| 1988-07-20 | @ MON | 94 | W 3-2 | - | | 17,476 | Jim Deshaies | John Dopson | Jim Deshaies | John Dopson | Larry Andersen | 397 | 389 | 8 |
| 1988-07-21 | vs PHI | 95 | W 2-0 | - | | 29,654 | Nolan Ryan | Mike Maddux | Nolan Ryan | Mike Maddux | | 399 | 389 | 10 |
| 1988-07-22 | vs PHI | 96 | W 5-3 | - | | 40,922 | Bob Knepper | David Palmer | Bob Knepper | David Palmer | Danny Darwin | 404 | 392 | 12 |
| 1988-07-23 | vs PHI | 97 | W 7-6 | - | | 32,931 | Joaquin Andujar | Shane Rawley | Dave Smith | Steve Bedrosian | | 411 | 398 | 13 |
| 1988-07-24 | vs PHI | 98 | L 4-6 | - | | 25,811 | Mike Scott | Kevin Gross | Kevin Gross | Mike Scott | Steve Bedrosian | 415 | 404 | 11 |
| 1988-07-26 | @ SDN | 99 | L 1-5 | - | | 16,691 | Jim Deshaies | Dennis Rasmussen | Dennis Rasmussen | Jim Deshaies | | 416 | 409 | 7 |
| 1988-07-27 | @ SDN | 100 | W 4-1 | - | | 15,850 | Nolan Ryan | Ed Whitson | Nolan Ryan | Ed Whitson | Dave Smith | 420 | 410 | 10 |
| 1988-07-28 | @ SDN | 101 | W 3-2 | - | | 17,030 | Bob Knepper | Eric Show | Bob Knepper | Eric Show | Larry Andersen | 423 | 412 | 11 |
| 1988-07-29 | @ LAN | 102 | W 3-1 | - | | 48,268 | Mike Scott | Shawn Hillegas | Mike Scott | Shawn Hillegas | | 426 | 413 | 13 |
| 1988-07-30 | @ LAN | 103 | W 14-6 | - | | 35,835 | Joaquin Andujar | Fernando Valenzuela | Danny Darwin | Brian Holton | | 440 | 419 | 21 |
| 1988-07-31 | @ LAN | 104 | L 1-6 | - | | 44,811 | Jim Deshaies | Orel Hershiser | Orel Hershiser | Jim Deshaies | | 441 | 425 | 16 |
| 1988-08-01 | @ SFN | 105 | L 1-4 | - | | 10,742 | Nolan Ryan | Atlee Hammaker | Atlee Hammaker | Nolan Ryan | | 442 | 429 | 13 |
| 1988-08-02 | @ SFN | 106 | W 13-10 | - | | 21,457 | Bob Knepper | Rick Reuschel | Danny Darwin | Ron Davis | Dave Smith | 455 | 439 | 16 |
| 1988-08-03 | @ SFN | 107 | W 3-2 | - | | 28,357 | Mike Scott | Joe Price | Mike Scott | Scott Garrelts | Dave Smith | 458 | 441 | 17 |
| 1988-08-05 | vs LAN | 108 | W 6-4 | - | | 43,426 | Jim Deshaies | Orel Hershiser | Jim Deshaies | Orel Hershiser | Dave Smith | 464 | 445 | 19 |
| 1988-08-06 | vs LAN | 109 | L 3-5 | - | | 43,521 | Nolan Ryan | Tim Belcher | Tim Belcher | Nolan Ryan | Jay Howell | 467 | 450 | 17 |
| 1988-08-07 | vs LAN | 110 | W 4-2 | - | | 40,339 | Bob Knepper | Tim Leary | Bob Knepper | Tim Leary | Juan Agosto | 471 | 452 | 19 |
| 1988-08-08 | vs LAN | 111 | W 10-0 | - | | 39,786 | Mike Scott | Shawn Hillegas | Mike Scott | Shawn Hillegas | | 481 | 452 | 29 |
| 1988-08-09 | vs SFN | 112 | W 3-2 | - | | 22,733 | Joaquin Andujar | Kelly Downs | Juan Agosto | Kelly Downs | Dave Smith | 484 | 454 | 30 |
| 1988-08-10 | vs SFN | 113 | L 0-5 | - | | 25,717 | Jim Deshaies | Don Robinson | Don Robinson | Jim Deshaies | | 484 | 459 | 25 |
| 1988-08-11 | vs SFN | 114 | L 0-6 | - | | 29,876 | Nolan Ryan | Atlee Hammaker | Atlee Hammaker | Nolan Ryan | | 484 | 465 | 19 |
| 1988-08-12 | vs SDN | 115 | L 3-4 | - | | 24,122 | Bob Knepper | Dennis Rasmussen | Dennis Rasmussen | Bob Knepper | Mark Davis | 487 | 469 | 18 |
| 1988-08-13 | vs SDN | 116 | W 1-0 | - | | 29,381 | Mike Scott | Ed Whitson | Mike Scott | Ed Whitson | | 488 | 469 | 19 |
| 1988-08-14 | vs SDN | 117 | L 1-6 | - | | 28,455 | Joaquin Andujar | Eric Show | Eric Show | Joaquin Andujar | | 489 | 475 | 14 |
| 1988-08-15 | vs SDN | 118 | W 7-3 | - | | 23,396 | Nolan Ryan | Andy Hawkins | Nolan Ryan | Andy Hawkins | | 496 | 478 | 18 |
| 1988-08-16 | @ SLN | 119 | L 0-3 | - | | 26,044 | Jim Deshaies | Scott Terry | Scott Terry | Jim Deshaies | Ken Dayley | 496 | 481 | 15 |
| 1988-08-17 | @ SLN | 120 | W 1-0 | - | | 25,343 | Dave Meads | Joe Magrane | Dave Meads | Joe Magrane | Dave Smith | 497 | 481 | 16 |
| 1988-08-18 | @ SLN | 121 | L 1-2 | - | | 27,355 | Mike Scott | Bob Forsch | Bob Forsch | Mike Scott | Todd Worrell | 498 | 483 | 15 |
| 1988-08-19 | @ PIT | 122 | W 5-1 | - | | 26,352 | Danny Darwin | Mike Dunne | Danny Darwin | Mike Dunne | | 503 | 484 | 19 |
| 1988-08-20 | @ PIT | 123 | L 1-2 | - | | 23,183 | Nolan Ryan | John Smiley | John Smiley | Nolan Ryan | Jim Gott | 504 | 486 | 18 |
| 1988-08-21 | @ PIT | 124 | W 2-1 | - | | 38,290 | Jim Deshaies | Bob Walk | Juan Agosto | Bob Kipper | | 506 | 487 | 19 |
| 1988-08-22 | @ CHN | 125 | W 9-7 | - | | 30,417 | Mike Scott | Rick Sutcliffe | Juan Agosto | Rich Gossage | | 515 | 494 | 21 |
| 1988-08-23 | @ CHN | 126 | L 3-9 | - | | 34,668 | Danny Darwin | Jamie Moyer | Jamie Moyer | Danny Darwin | | 518 | 503 | 15 |
| 1988-08-24 | @ CHN | 127 | L 2-3 | - | | 35,065 | Nolan Ryan | Greg Maddux | Jeff Pico | Juan Agosto | | 520 | 506 | 14 |
| 1988-08-26 | vs PIT | 128 | W 2-0 | - | | 27,650 | Jim Deshaies | John Smiley | Jim Deshaies | John Smiley | | 522 | 506 | 16 |
| 1988-08-27 | vs PIT | 129 | W 3-1 | - | | 25,993 | Mike Scott | Bob Walk | Dave Meads | Bob Walk | Juan Agosto | 525 | 507 | 18 |
| 1988-08-28 | vs PIT | 130 | L 3-4 | - | | 20,368 | Danny Darwin | Doug Drabek | Doug Drabek | Danny Darwin | Jim Gott | 528 | 511 | 17 |
| 1988-08-29 | vs CHN | 131 | L 1-2 | - | | 23,142 | Nolan Ryan | Greg Maddux | Scott Sanderson | Larry Andersen | Drew Hall | 529 | 513 | 16 |
| 1988-08-30 | vs CHN | 132 | W 7-4 | - | | 17,053 | Joaquin Andujar | Calvin Schiraldi | Joaquin Andujar | Calvin Schiraldi | Dave Smith | 536 | 517 | 19 |
| 1988-08-31 | vs CHN | 133 | L 1-3 | - | | 14,200 | Jim Deshaies | Rick Sutcliffe | Rick Sutcliffe | Jim Deshaies | | 537 | 520 | 17 |
| 1988-09-02 | vs SLN | 134 | L 0-2 | - | | 16,054 | Mike Scott | Joe Magrane | Joe Magrane | Mike Scott | | 537 | 522 | 15 |
| 1988-09-03 | vs SLN | 135 | W 10-1 | - | | 24,463 | Nolan Ryan | Larry McWilliams | Nolan Ryan | Larry McWilliams | | 547 | 523 | 24 |
| 1988-09-04 | vs SLN | 136 | W 4-3 | - | | 20,309 | Bob Knepper | Greg Mathews | Bob Knepper | Greg Mathews | Dave Smith | 551 | 526 | 25 |
| 1988-09-05 | vs CIN | 137 | W 3-0 | - | | 17,128 | Bob Forsch | Norm Charlton | Bob Forsch | Norm Charlton | Dave Smith | 554 | 526 | 28 |
| 1988-09-06 | vs CIN | 138 | L 3-10 | - | | 13,345 | Jim Deshaies | Tom Browning | Tom Browning | Jim Deshaies | | 557 | 536 | 21 |
| 1988-09-07 | @ LAN | 139 | L 1-4 | - | | 35,874 | Mike Scott | Tim Leary | Tim Leary | Mike Scott | Jay Howell | 558 | 540 | 18 |
| 1988-09-08 | @ LAN | 140 | W 2-1 | - | | 36,504 | Nolan Ryan | John Tudor | Nolan Ryan | John Tudor | | 560 | 541 | 19 |
| 1988-09-09 | @ SFN | 141 | W 4-3 | - | | 13,670 | Bob Knepper | Rick Reuschel | Danny Darwin | Scott Garrelts | | 564 | 544 | 20 |
| 1988-09-10 | @ SFN | 142 | L 2-3 | - | | 20,054 | Bob Forsch | Trevor Wilson | Craig Lefferts | Juan Agosto | Lary Sorensen | 566 | 547 | 19 |
| 1988-09-11 | @ SFN | 143 | W 4-1 | - | | 28,304 | Jim Deshaies | Atlee Hammaker | Jim Deshaies | Atlee Hammaker | | 570 | 548 | 22 |
| 1988-09-13 | @ CIN | 144 | L 2-5 | - | | 15,067 | Mike Scott | Jose Rijo | Jose Rijo | Mike Scott | John Franco | 572 | 553 | 19 |
| 1988-09-14 | @ CIN | 145 | W 7-1 | - | | 16,833 | Nolan Ryan | Danny Jackson | Nolan Ryan | Danny Jackson | | 579 | 554 | 25 |
| 1988-09-15 | @ CIN | 146 | L 5-7 | - | | 17,610 | Bob Forsch | Norm Charlton | Norm Charlton | Bob Forsch | John Franco | 584 | 561 | 23 |
| 1988-09-16 | vs SFN | 147 | L 4-5 | - | | 14,344 | Bob Knepper | Atlee Hammaker | Atlee Hammaker | Bob Knepper | Craig Lefferts | 588 | 566 | 22 |
| 1988-09-17 | vs SFN | 148 | L 2-4 | - | | 19,593 | Jim Deshaies | Rick Reuschel | Rick Reuschel | Jim Deshaies | | 590 | 570 | 20 |
| 1988-09-18 | vs SFN | 149 | L 3-10 | - | | 13,097 | Mike Scott | Don Robinson | Don Robinson | Mike Scott | | 593 | 580 | 13 |
| 1988-09-19 | vs LAN | 150 | L 0-1 | - | | 16,173 | Nolan Ryan | Orel Hershiser | Orel Hershiser | Danny Darwin | | 593 | 581 | 12 |
| 1988-09-20 | vs LAN | 151 | L 0-6 | - | | 12,291 | Bob Forsch | Tim Belcher | Tim Belcher | Bob Forsch | | 593 | 587 | 6 |
| 1988-09-21 | vs ATL | 152 | W 1-0 | - | | 7,411 | Bob Knepper | Pete Smith | Bob Knepper | Pete Smith | | 594 | 587 | 7 |
| 1988-09-22 | vs ATL | 153 | W 3-2 | - | | 19,633 | Jim Deshaies | Tom Glavine | Jim Deshaies | Tom Glavine | Dave Smith | 597 | 589 | 8 |
| 1988-09-23 | @ SDN | 154 | L 3-4 | - | | 9,929 | Mike Scott | Andy Hawkins | Dave Leiper | Danny Darwin | | 600 | 593 | 7 |
| 1988-09-24 | @ SDN | 155 | L 0-3 | - | | 21,252 | Jeff Heathcock | Ed Whitson | Ed Whitson | Jeff Heathcock | | 600 | 596 | 4 |
| 1988-09-25 | @ SDN | 156 | L 1-9 | - | | 11,796 | Bob Forsch | Greg Harris | Greg Harris | Bob Forsch | | 601 | 605 | -4 |
| 1988-09-27 | @ ATL | 157 | W 3-2 | - | | 3,071 | Jim Deshaies | Pete Smith | Danny Darwin | Joe Boever | | 604 | 607 | -3 |
| 1988-09-28 | @ ATL | 158 | L 3-4 | - | | 2,822 | Bob Knepper | Tom Glavine | Charlie Puleo | Jeff Heathcock | | 607 | 611 | -4 |
| 1988-09-29 | @ ATL | 159 | W 5-4 | - | | 5,789 | Mike Scott | John Smoltz | Mike Scott | John Smoltz | Dave Smith | 612 | 615 | -3 |
| 1988-09-30 | vs SDN | 160 | L 1-5 | - | | 9,711 | Dave Meads | Ed Whitson | Greg Harris | Dave Meads | | 613 | 620 | -7 |
| 1988-10-01 | vs SDN | 161 | L 3-6 | - | | 10,452 | Bob Forsch | Greg Booker | Greg Booker | Bob Forsch | Mark Davis | 616 | 626 | -10 |
| 1988-10-02 | vs SDN | 162 | L 1-5 | - | | 15,056 | Jim Deshaies | Dennis Rasmussen | Dennis Rasmussen | Jim Deshaies | | 617 | 631 | -14 |