| 1990-04-09 | @ CAL | 1 | W 7-4 | 1-0 | 3 | 38,406 | Brian Holman | Bert Blyleven | Brian Holman | Bert Blyleven | Mike Schooler | 7 | 4 | 3 |
| 1990-04-10 | @ CAL | 2 | L 0-7 | 1-1 | 3 | 23,508 | Randy Johnson | Chuck Finley | Chuck Finley | Randy Johnson | Mark Eichhorn | 7 | 11 | -4 |
| 1990-04-11 | @ CAL | 3 | L 0-1 | 1-2 | 7 | 25,632 | Erik Hanson | Mark Langston | Mark Langston | Gary Eave | Mike Witt | 7 | 12 | -5 |
| 1990-04-13 | vs OAK | 4 | L 7-15 | 1-3 | 7 | 54,874 | Scott Bankhead | Scott Sanderson | Scott Sanderson | Scott Bankhead | | 14 | 27 | -13 |
| 1990-04-14 | vs OAK | 5 | L 2-5 | 1-4 | 7 | 25,961 | Matt Young | Dave Stewart | Dave Stewart | Matt Young | Dennis Eckersley | 16 | 32 | -16 |
| 1990-04-15 | vs OAK | 6 | L 0-3 | 1-5 | 7 | 17,139 | Brian Holman | Bob Welch | Bob Welch | Brian Holman | Dennis Eckersley | 16 | 35 | -19 |
| 1990-04-16 | vs MIN | 7 | W 6-3 | 2-5 | 6 | 12,538 | Randy Johnson | David West | Randy Johnson | David West | Mike Schooler | 22 | 38 | -16 |
| 1990-04-17 | vs MIN | 8 | L 5-6 | 2-6 | 7 | 9,053 | Erik Hanson | Allan Anderson | Juan Berenguer | Keith Comstock | Rick Aguilera | 27 | 44 | -17 |
| 1990-04-18 | vs MIN | 9 | L 3-4 | 2-7 | 7 | 9,425 | Matt Young | Roy Smith | Terry Leach | Matt Young | Rick Aguilera | 30 | 48 | -18 |
| 1990-04-19 | @ OAK | 10 | L 2-5 | 2-8 | 7 | 23,979 | Gary Eave | Dave Stewart | Dave Stewart | Gary Eave | | 32 | 53 | -21 |
| 1990-04-20 | @ OAK | 11 | W 6-1 | 3-8 | 7 | 44,911 | Brian Holman | Bob Welch | Brian Holman | Bob Welch | | 38 | 54 | -16 |
| 1990-04-21 | @ OAK | 12 | L 6-7 | 3-9 | 7 | 33,277 | Randy Johnson | Mike Moore | Dennis Eckersley | Jerry Reed | | 44 | 61 | -17 |
| 1990-04-22 | @ OAK | 13 | W 5-2 | 4-9 | 7 | 40,901 | Erik Hanson | Scott Sanderson | Erik Hanson | Scott Sanderson | Michael Jackson | 49 | 63 | -14 |
| 1990-04-24 | @ NYA | 14 | L 2-6 | 4-10 | 7 | 17,018 | Matt Young | Dave LaPoint | Dave LaPoint | Matt Young | | 51 | 69 | -18 |
| 1990-04-25 | @ NYA | 15 | W 5-2 | 5-10 | 7 | 15,537 | Brian Holman | Pascual Perez | Brian Holman | Pascual Perez | Mike Schooler | 56 | 71 | -15 |
| 1990-04-26 | @ NYA | 16 | W 6-2 | 6-10 | 6 | 15,857 | Randy Johnson | Andy Hawkins | Randy Johnson | Andy Hawkins | Bill Swift | 62 | 73 | -11 |
| 1990-04-27 | @ BAL | 17 | W 4-3 | 7-10 | 6 | 23,183 | Erik Hanson | Jeff Ballard | Erik Hanson | Jeff Ballard | Mike Schooler | 66 | 76 | -10 |
| 1990-04-28 | @ BAL | 18 | W 4-3 | 8-10 | 4 | 31,017 | Matt Young | Pete Harnisch | Michael Jackson | Kevin Hickey | Mike Schooler | 70 | 79 | -9 |
| 1990-04-29 | @ BAL | 19 | L 4-5 | 8-11 | 5 | 24,468 | Gary Eave | Dave Johnson | Mark Williamson | Michael Jackson | | 74 | 84 | -10 |
| 1990-04-30 | @ BOS | 20 | L 0-11 | 8-12 | 5 | 18,540 | Brian Holman | Mike Boddicker | Mike Boddicker | Brian Holman | | 74 | 95 | -21 |
| 1990-05-01 | @ BOS | 21 | L 2-8 | 8-13 | 6 | 20,786 | Randy Johnson | Eric Hetzel | Eric Hetzel | Randy Johnson | | 76 | 103 | -27 |
| 1990-05-02 | @ BOS | 22 | W 9-2 | 9-13 | 6 | 23,977 | Erik Hanson | Greg Harris | Erik Hanson | Greg Harris | | 85 | 105 | -20 |
| 1990-05-03 | vs CAL | 23 | W 10-8 | 10-13 | 6 | 12,279 | Matt Young | Chuck Finley | Brent Knackert | Chuck Finley | Mike Schooler | 95 | 113 | -18 |
| 1990-05-04 | vs BAL | 24 | L 8-9 | 10-14 | 6 | 23,797 | Gary Eave | Pete Harnisch | Kevin Hickey | Michael Jackson | Gregg Olson | 103 | 122 | -19 |
| 1990-05-05 | vs BAL | 25 | W 5-2 | 11-14 | 5 | 16,489 | Brian Holman | Dave Johnson | Brian Holman | Dave Johnson | Mike Schooler | 108 | 124 | -16 |
| 1990-05-06 | vs BAL | 26 | W 5-4 | 12-14 | 5 | 36,919 | Randy Johnson | Bob Milacki | Bill Swift | Mark Williamson | Mike Schooler | 113 | 128 | -15 |
| 1990-05-07 | vs BOS | 27 | L 4-5 | 12-15 | 5 | 19,549 | Erik Hanson | Greg Harris | Greg Harris | Erik Hanson | Rob Murphy | 117 | 133 | -16 |
| 1990-05-08 | vs BOS | 28 | W 2-1 | 13-15 | 5 | 11,503 | Matt Young | Dana Kiecker | Bill Swift | Wes Gardner | | 119 | 134 | -15 |
| 1990-05-09 | vs BOS | 29 | L 1-4 | 13-16 | 5 | 14,192 | Gary Eave | Roger Clemens | Roger Clemens | Gary Eave | | 120 | 138 | -18 |
| 1990-05-10 | vs CAL | 30 | W 5-2 | 14-16 | 5 | 13,958 | Brian Holman | Kirk McCaskill | Brian Holman | Kirk McCaskill | Mike Schooler | 125 | 140 | -15 |
| 1990-05-11 | vs NYA | 31 | L 5-8 | 14-17 | 5 | 26,699 | Randy Johnson | Andy Hawkins | Lee Guetterman | Gene Harris | Dave Righetti | 130 | 148 | -18 |
| 1990-05-12 | vs NYA | 32 | L 1-4 | 14-18 | 5 | 43,977 | Erik Hanson | Tim Leary | Tim Leary | Erik Hanson | | 131 | 152 | -21 |
| 1990-05-13 | vs NYA | 33 | W 10-5 | 15-18 | 5 | 18,492 | Matt Young | Greg Cadaret | Matt Young | Greg Cadaret | | 141 | 157 | -16 |
| 1990-05-15 | @ TOR | 34 | W 4-3 | 16-18 | 4 | 41,108 | Gary Eave | Steve Cummings | Keith Comstock | Jim Acker | Mike Schooler | 145 | 160 | -15 |
| 1990-05-16 | @ TOR | 35 | W 4-2 | 17-18 | 4 | 45,640 | Brian Holman | Todd Stottlemyre | Brian Holman | Todd Stottlemyre | Mike Schooler | 149 | 162 | -13 |
| 1990-05-17 | @ TOR | 36 | W 14-6 | 18-18 | 4 | 47,283 | Randy Johnson | Jimmy Key | Randy Johnson | Jimmy Key | | 163 | 168 | -5 |
| 1990-05-18 | @ CLE | 37 | L 0-5 | 18-19 | 4 | 28,024 | Erik Hanson | Buddy Black | Buddy Black | Erik Hanson | | 163 | 173 | -10 |
| 1990-05-19 | @ CLE | 38 | L 3-4 | 18-20 | 4 | 15,092 | Matt Young | John Farrell | Jesse Orosco | Matt Young | Doug Jones | 166 | 177 | -11 |
| 1990-05-20 | @ CLE | 39 | W 8-7 | 19-20 | 4 | 20,242 | Scott Bankhead | Greg Swindell | Mike Schooler | Jesse Orosco | | 174 | 184 | -10 |
| 1990-05-21 | @ MIL | 40 | W 9-4 | 20-20 | 4 | 12,456 | Brian Holman | Teddy Higuera | Bryan Clark | Dan Plesac | | 183 | 188 | -5 |
| 1990-05-22 | @ MIL | 41 | L 2-3 | 20-21 | 4 | 17,329 | Randy Johnson | Mark Knudson | Mark Knudson | Bill Swift | | 185 | 191 | -6 |
| 1990-05-23 | vs CLE | 42 | W 4-1 | 21-21 | 4 | 10,207 | Erik Hanson | Buddy Black | Erik Hanson | Buddy Black | Mike Schooler | 189 | 192 | -3 |
| 1990-05-24 | vs CLE | 43 | L 3-5 | 21-22 | 4 | 10,271 | Matt Young | John Farrell | Jesse Orosco | Matt Young | Doug Jones | 192 | 197 | -5 |
| 1990-05-25 | vs TOR | 44 | L 1-3 | 21-23 | 4 | 15,334 | Scott Bankhead | Willie Blair | Jim Acker | Bill Swift | Tom Henke | 193 | 200 | -7 |
| 1990-05-26 | vs TOR | 45 | L 4-11 | 21-24 | 5 | 25,004 | Brian Holman | Todd Stottlemyre | Frank Wills | Brian Holman | | 197 | 211 | -14 |
| 1990-05-27 | vs TOR | 46 | L 1-5 | 21-25 | 5 | 25,858 | Randy Johnson | John Cerutti | John Cerutti | Randy Johnson | | 198 | 216 | -18 |
| 1990-05-28 | vs MIL | 47 | W 4-3 | 22-25 | 5 | 22,495 | Erik Hanson | Jaime Navarro | Erik Hanson | Jaime Navarro | Mike Schooler | 202 | 219 | -17 |
| 1990-05-29 | vs MIL | 48 | L 3-5 | 22-26 | 5 | 8,210 | Matt Young | Mark Knudson | Chuck Crim | Michael Jackson | Dan Plesac | 205 | 224 | -19 |
| 1990-05-30 | vs MIL | 49 | W 2-1 | 23-26 | 5 | 10,481 | Brent Knackert | Chris Bosio | Bryan Clark | Chris Bosio | Mike Schooler | 207 | 225 | -18 |
| 1990-06-01 | vs DET | 50 | L 7-9 | 23-27 | 5 | 14,298 | Scott Bankhead | Jack Morris | Jack Morris | Scott Bankhead | Mike Henneman | 214 | 234 | -20 |
| 1990-06-02 | vs DET | 51 | W 2-0 | 24-27 | 5 | 20,014 | Randy Johnson | Jeff Robinson | Randy Johnson | Jeff Robinson | | 216 | 234 | -18 |
| 1990-06-03 | vs DET | 52 | L 0-2 | 24-28 | 5 | 23,636 | Erik Hanson | Frank Tanana | Frank Tanana | Erik Hanson | Mike Henneman | 216 | 236 | -20 |
| 1990-06-05 | @ CHA | 53 | W 10-6 | 25-28 | 5 | 9,036 | Brian Holman | Greg Hibbard | Brian Holman | Greg Hibbard | | 226 | 242 | -16 |
| 1990-06-06 | @ CHA | 54 | L 0-5 | 25-29 | 5 | 14,479 | Matt Young | Melido Perez | Melido Perez | Matt Young | | 226 | 247 | -21 |
| 1990-06-07 | @ CHA | 55 | W 2-1 | 26-29 | 5 | 15,383 | Randy Johnson | Adam Peterson | Randy Johnson | Donn Pall | | 228 | 248 | -20 |
| 1990-06-08 | @ DET | 56 | W 5-2 | 27-30 | 5 | 0 | Erik Hanson | Frank Tanana | Erik Hanson | Frank Tanana | Michael Jackson | 233 | 250 | -17 |
| 1990-06-08 | @ DET | 57 | L 3-6 | 27-30 | 5 | 18,718 | Brent Knackert | Jeff Robinson | Mike Henneman | Keith Comstock | | 236 | 256 | -20 |
| 1990-06-09 | @ DET | 58 | W 5-2 | 28-30 | 5 | 21,137 | Russ Swan | Dan Petry | Russ Swan | Dan Petry | | 241 | 258 | -17 |
| 1990-06-10 | @ DET | 59 | L 3-4 | 28-31 | 5 | 22,174 | Brian Holman | Jack Morris | Jack Morris | Brian Holman | Mike Henneman | 244 | 262 | -18 |
| 1990-06-11 | vs CHA | 60 | L 1-3 | 28-32 | 5 | 20,627 | Matt Young | Melido Perez | Melido Perez | Matt Young | Ken Patterson | 245 | 265 | -20 |
| 1990-06-12 | vs CHA | 61 | W 5-2 | 29-32 | 5 | 10,138 | Randy Johnson | Adam Peterson | Randy Johnson | Adam Peterson | Mike Schooler | 250 | 267 | -17 |
| 1990-06-13 | vs CHA | 62 | L 2-11 | 29-33 | 5 | 12,468 | Erik Hanson | Jack McDowell | Jack McDowell | Erik Hanson | | 252 | 278 | -26 |
| 1990-06-14 | vs TEX | 63 | W 5-4 | 30-33 | 5 | 9,421 | Russ Swan | Mike Jeffcoat | Keith Comstock | Kenny Rogers | | 257 | 282 | -25 |
| 1990-06-15 | vs TEX | 64 | L 3-4 | 30-34 | 5 | 17,953 | Brian Holman | Kevin Brown | Kevin Brown | Brian Holman | | 260 | 286 | -26 |
| 1990-06-16 | vs TEX | 65 | W 5-0 | 31-34 | 5 | 37,248 | Matt Young | Nolan Ryan | Matt Young | Nolan Ryan | | 265 | 286 | -21 |
| 1990-06-17 | vs TEX | 66 | W 6-3 | 32-34 | 5 | 18,907 | Randy Johnson | Bobby Witt | Randy Johnson | Bobby Witt | | 271 | 289 | -18 |
| 1990-06-18 | @ KCA | 67 | L 2-6 | 32-35 | 5 | 35,217 | Erik Hanson | Mark Gubicza | Mark Gubicza | Erik Hanson | | 273 | 295 | -22 |
| 1990-06-19 | @ KCA | 68 | L 1-2 | 32-36 | 5 | 28,610 | Russ Swan | Steve Farr | Steve Farr | Russ Swan | Jeff Montgomery | 274 | 297 | -23 |
| 1990-06-20 | @ KCA | 69 | W 3-2 | 33-36 | 4 | 29,085 | Brian Holman | Kevin Appier | Brian Holman | Kevin Appier | Mike Schooler | 277 | 299 | -22 |
| 1990-06-22 | @ TEX | 70 | L 2-5 | 33-37 | 5 | 40,285 | Matt Young | Nolan Ryan | Nolan Ryan | Matt Young | | 279 | 304 | -25 |
| 1990-06-23 | @ TEX | 71 | W 8-6 | 34-37 | 5 | 34,336 | Randy Johnson | Bobby Witt | Michael Jackson | Kenny Rogers | Mike Schooler | 287 | 310 | -23 |
| 1990-06-24 | @ TEX | 72 | W 11-5 | 35-37 | 4 | 24,421 | Erik Hanson | Charlie Hough | Erik Hanson | Charlie Hough | | 298 | 315 | -17 |
| 1990-06-26 | vs KCA | 73 | L 1-4 | 35-38 | 5 | 19,004 | Brian Holman | Tom Gordon | Tom Gordon | Brian Holman | Jeff Montgomery | 299 | 319 | -20 |
| 1990-06-27 | vs KCA | 74 | W 3-2 | 36-38 | 4 | 17,362 | Matt Young | Kevin Appier | Michael Jackson | Mark Davis | Mike Schooler | 302 | 321 | -19 |
| 1990-06-28 | vs KCA | 75 | W 6-4 | 37-38 | 4 | 15,425 | Russ Swan | Bret Saberhagen | Keith Comstock | Mark Davis | Mike Schooler | 308 | 325 | -17 |
| 1990-06-29 | vs MIL | 76 | W 4-2 | 38-38 | 4 | 13,685 | Randy Johnson | Ron Robinson | Randy Johnson | Chuck Crim | Mike Schooler | 312 | 327 | -15 |
| 1990-06-30 | vs MIL | 77 | W 6-2 | 39-38 | 3 | 26,746 | Erik Hanson | Teddy Higuera | Erik Hanson | Teddy Higuera | | 318 | 329 | -11 |
| 1990-07-01 | vs MIL | 78 | W 6-5 | 40-38 | 3 | 17,225 | Brian Holman | Dennis Powell | Keith Comstock | Paul Mirabella | | 324 | 334 | -10 |
| 1990-07-03 | @ CLE | 79 | L 4-9 | 40-39 | 3 | 45,242 | Matt Young | Al Nipper | Al Nipper | Matt Young | | 328 | 343 | -15 |
| 1990-07-04 | @ CLE | 80 | W 3-2 | 41-39 | 3 | 14,948 | Randy Johnson | Charles Nagy | Randy Johnson | Charles Nagy | Mike Schooler | 331 | 345 | -14 |
| 1990-07-05 | @ CLE | 81 | W 4-1 | 42-39 | 3 | 12,405 | Erik Hanson | Tom Candiotti | Erik Hanson | Tom Candiotti | Mike Schooler | 335 | 346 | -11 |
| 1990-07-06 | @ TOR | 82 | L 0-1 | 42-40 | 3 | 49,872 | Brian Holman | David Wells | David Wells | Brian Holman | Tom Henke | 335 | 347 | -12 |
| 1990-07-07 | @ TOR | 83 | L 2-4 | 42-41 | 3 | 48,899 | Russ Swan | Jimmy Key | Jimmy Key | Russ Swan | Duane Ward | 337 | 351 | -14 |
| 1990-07-08 | @ TOR | 84 | W 6-3 | 43-41 | 3 | 49,816 | Matt Young | Todd Stottlemyre | Matt Young | Todd Stottlemyre | | 343 | 354 | -11 |
| 1990-07-11 | vs CAL | 85 | W 2-1 | 44-41 | 3 | 18,357 | Erik Hanson | Mark Langston | Erik Hanson | Mark Langston | Mike Schooler | 345 | 355 | -10 |
| 1990-07-12 | vs CLE | 86 | L 4-5 | 44-42 | 3 | 11,291 | Brian Holman | Greg Swindell | Rudy Seanez | Mike Schooler | Doug Jones | 349 | 360 | -11 |
| 1990-07-13 | vs CLE | 87 | L 7-13 | 44-43 | 3 | 12,381 | Matt Young | Tom Candiotti | Tom Candiotti | Matt Young | | 356 | 373 | -17 |
| 1990-07-14 | vs CLE | 88 | L 0-3 | 44-44 | 3 | 17,735 | Randy Johnson | Buddy Black | Buddy Black | Randy Johnson | Doug Jones | 356 | 376 | -20 |
| 1990-07-15 | vs CLE | 89 | W 7-0 | 45-44 | 3 | 12,597 | Bill Swift | Charles Nagy | Bill Swift | Charles Nagy | | 363 | 376 | -13 |
| 1990-07-16 | vs TOR | 90 | L 3-4 | 45-45 | 3 | 24,833 | Erik Hanson | Jimmy Key | Jimmy Key | Erik Hanson | Tom Henke | 366 | 380 | -14 |
| 1990-07-17 | vs TOR | 91 | W 7-5 | 46-45 | 3 | 14,259 | Brian Holman | David Wells | Michael Jackson | Duane Ward | Mike Schooler | 373 | 385 | -12 |
| 1990-07-18 | vs TOR | 92 | W 5-2 | 47-45 | 3 | 15,868 | Matt Young | Todd Stottlemyre | Matt Young | Todd Stottlemyre | | 378 | 387 | -9 |
| 1990-07-19 | @ MIL | 93 | L 0-4 | 47-46 | 3 | 17,845 | Randy Johnson | Bill Krueger | Bill Krueger | Randy Johnson | Jaime Navarro | 378 | 391 | -13 |
| 1990-07-20 | @ MIL | 94 | W 6-4 | 48-46 | 3 | 27,522 | Bill Swift | Chris Bosio | Keith Comstock | Randy Veres | Mike Schooler | 384 | 395 | -11 |
| 1990-07-21 | @ MIL | 95 | L 3-10 | 48-47 | 3 | 38,896 | Erik Hanson | Ron Robinson | Ron Robinson | Erik Hanson | Randy Veres | 387 | 405 | -18 |
| 1990-07-22 | @ MIL | 96 | W 4-3 | 49-47 | 3 | 37,638 | Brian Holman | Teddy Higuera | Brian Holman | Teddy Higuera | Mike Schooler | 391 | 408 | -17 |
| 1990-07-24 | @ MIN | 97 | W 8-2 | 50-47 | 3 | 17,380 | Matt Young | David West | Matt Young | David West | | 399 | 410 | -11 |
| 1990-07-25 | @ MIN | 98 | L 0-6 | 50-48 | 3 | 21,384 | Randy Johnson | Kevin Tapani | Kevin Tapani | Randy Johnson | John Candelaria | 399 | 416 | -17 |
| 1990-07-26 | @ MIN | 99 | W 6-4 | 51-48 | 3 | 29,455 | Bill Swift | Allan Anderson | Bill Swift | Allan Anderson | Mike Schooler | 405 | 420 | -15 |
| 1990-07-27 | vs CAL | 100 | W 8-1 | 52-48 | 3 | 19,260 | Erik Hanson | Mark Langston | Erik Hanson | Mark Langston | | 413 | 421 | -8 |
| 1990-07-28 | vs CAL | 101 | W 2-1 | 53-48 | 3 | 28,039 | Brian Holman | Kirk McCaskill | Brian Holman | Kirk McCaskill | Mike Schooler | 415 | 422 | -7 |
| 1990-07-29 | vs CAL | 102 | L 2-6 | 53-49 | 3 | 18,388 | Matt Young | Jim Abbott | Jim Abbott | Matt Young | Bryan Harvey | 417 | 428 | -11 |
| 1990-07-30 | @ OAK | 103 | L 2-6 | 53-50 | 3 | 41,752 | Randy Johnson | Scott Sanderson | Rick Honeycutt | Randy Johnson | Dennis Eckersley | 419 | 434 | -15 |
| 1990-07-31 | @ OAK | 104 | W 7-2 | 54-50 | 3 | 30,130 | Bill Swift | Mike Moore | Bill Swift | Mike Moore | | 426 | 436 | -10 |
| 1990-08-01 | @ OAK | 105 | L 0-1 | 54-51 | 4 | 31,509 | Erik Hanson | Dave Stewart | Dave Stewart | Mike Schooler | | 426 | 437 | -11 |
| 1990-08-02 | vs MIN | 106 | W 7-2 | 55-51 | 4 | 14,004 | Brian Holman | Mark Guthrie | Brian Holman | Mark Guthrie | | 433 | 439 | -6 |
| 1990-08-03 | vs MIN | 107 | L 2-6 | 55-52 | 4 | 13,818 | Matt Young | Scott Erickson | Rick Aguilera | Mike Schooler | | 435 | 445 | -10 |
| 1990-08-04 | vs MIN | 108 | W 4-3 | 56-52 | 4 | 20,508 | Randy Johnson | Kevin Tapani | Michael Jackson | Jack Savage | | 439 | 448 | -9 |
| 1990-08-05 | vs MIN | 109 | W 4-0 | 57-52 | 4 | 17,248 | Bill Swift | Allan Anderson | Gene Harris | Allan Anderson | Keith Comstock | 443 | 448 | -5 |
| 1990-08-07 | vs NYA | 110 | L 1-3 | 57-53 | 4 | 17,823 | Erik Hanson | Mike Witt | Mike Witt | Erik Hanson | Dave Righetti | 444 | 451 | -7 |
| 1990-08-08 | vs NYA | 111 | L 4-6 | 57-54 | 4 | 14,081 | Brian Holman | Chuck Cary | Eric Plunk | Keith Comstock | Dave Righetti | 448 | 457 | -9 |
| 1990-08-09 | vs NYA | 112 | L 0-1 | 57-55 | 4 | 15,329 | Matt Young | Tim Leary | Tim Leary | Matt Young | Lee Guetterman | 448 | 458 | -10 |
| 1990-08-10 | vs BOS | 113 | W 4-1 | 58-55 | 3 | 20,506 | Randy Johnson | Dana Kiecker | Randy Johnson | Dana Kiecker | Mike Schooler | 452 | 459 | -7 |
| 1990-08-11 | vs BOS | 114 | L 2-4 | 58-56 | 4 | 30,113 | Bill Swift | Mike Boddicker | Daryl Irvine | Mike Schooler | | 454 | 463 | -9 |
| 1990-08-12 | vs BOS | 115 | L 2-7 | 58-57 | 4 | 25,553 | Erik Hanson | Tom Bolton | Tom Bolton | Michael Jackson | | 456 | 470 | -14 |
| 1990-08-13 | vs BAL | 116 | L 2-3 | 58-58 | 4 | 21,233 | Brian Holman | Ben McDonald | Ben McDonald | Brian Holman | Gregg Olson | 458 | 473 | -15 |
| 1990-08-14 | vs BAL | 117 | W 7-1 | 59-58 | 4 | 11,239 | Matt Young | Dave Johnson | Matt Young | Dave Johnson | | 465 | 474 | -9 |
| 1990-08-15 | vs BAL | 118 | W 2-0 | 60-58 | 4 | 15,308 | Randy Johnson | Pete Harnisch | Randy Johnson | Pete Harnisch | | 467 | 474 | -7 |
| 1990-08-17 | @ NYA | 119 | L 2-3 | 60-59 | 4 | 28,802 | Bill Swift | Andy Hawkins | Lee Guetterman | Bill Swift | Dave Righetti | 469 | 477 | -8 |
| 1990-08-18 | @ NYA | 120 | L 0-6 | 60-60 | 4 | 30,532 | Brian Holman | Mike Witt | Mike Witt | Brian Holman | | 469 | 483 | -14 |
| 1990-08-19 | @ NYA | 121 | L 1-3 | 60-61 | 4 | 35,056 | Matt Young | Tim Leary | Tim Leary | Matt Young | Dave Righetti | 470 | 486 | -16 |
| 1990-08-20 | @ TEX | 122 | L 5-6 | 60-62 | 5 | 16,177 | Erik Hanson | Bobby Witt | Mike Jeffcoat | Michael Jackson | | 475 | 492 | -17 |
| 1990-08-21 | @ TEX | 123 | W 4-3 | 61-62 | 4 | 19,254 | Randy Johnson | Charlie Hough | Randy Johnson | Charlie Hough | Mike Schooler | 479 | 495 | -16 |
| 1990-08-22 | @ TEX | 124 | L 4-5 | 61-63 | 5 | 31,780 | Bill Swift | Nolan Ryan | Nolan Ryan | Bill Swift | Brad Arnsberg | 483 | 500 | -17 |
| 1990-08-23 | @ KCA | 125 | L 1-4 | 61-64 | 5 | 31,863 | Brian Holman | Kevin Appier | Kevin Appier | Brian Holman | Jeff Montgomery | 484 | 504 | -20 |
| 1990-08-24 | @ KCA | 126 | L 3-4 | 61-65 | 5 | 30,888 | Matt Young | Andy McGaffigan | Steve Farr | Gene Harris | | 487 | 508 | -21 |
| 1990-08-25 | @ KCA | 127 | W 6-3 | 62-65 | 5 | 33,671 | Erik Hanson | Storm Davis | Erik Hanson | Storm Davis | Bill Swift | 493 | 511 | -18 |
| 1990-08-26 | @ KCA | 128 | L 2-8 | 62-66 | 6 | 26,832 | Randy Johnson | Jim Campbell | Jim Campbell | Randy Johnson | | 495 | 519 | -24 |
| 1990-08-28 | vs DET | 129 | W 4-3 | 63-66 | 6 | 12,201 | Brian Holman | Jack Morris | Keith Comstock | Paul Gibson | | 499 | 522 | -23 |
| 1990-08-29 | vs DET | 130 | L 2-4 | 63-67 | 6 | 13,105 | Matt Young | Walt Terrell | Walt Terrell | Matt Young | Jerry Gleaton | 501 | 526 | -25 |
| 1990-08-30 | vs DET | 131 | L 2-3 | 63-68 | 6 | 10,055 | Erik Hanson | Frank Tanana | Mike Henneman | Michael Jackson | | 503 | 529 | -26 |
| 1990-08-31 | vs KCA | 132 | W 5-2 | 64-68 | 6 | 27,166 | Randy Johnson | Storm Davis | Randy Johnson | Storm Davis | Bill Swift | 508 | 531 | -23 |
| 1990-09-01 | vs KCA | 133 | W 3-0 | 65-68 | 6 | 24,160 | Russ Swan | Chris Codiroli | Russ Swan | Steve Crawford | Bill Swift | 511 | 531 | -20 |
| 1990-09-02 | vs KCA | 134 | L 0-8 | 65-69 | 6 | 17,307 | Brian Holman | Tom Gordon | Tom Gordon | Brian Holman | | 511 | 539 | -28 |
| 1990-09-03 | @ BAL | 135 | W 6-2 | 66-69 | 6 | 23,981 | Matt Young | Anthony Telford | Matt Young | Anthony Telford | | 517 | 541 | -24 |
| 1990-09-04 | @ BAL | 136 | W 7-2 | 67-69 | 5 | 22,315 | Erik Hanson | Pete Harnisch | Erik Hanson | Pete Harnisch | | 524 | 543 | -19 |
| 1990-09-05 | @ BAL | 137 | W 9-5 | 68-69 | 5 | 18,742 | Randy Johnson | John Mitchell | Keith Comstock | Kevin Hickey | | 533 | 548 | -15 |
| 1990-09-07 | @ BOS | 138 | L 4-5 | 68-70 | 5 | 32,868 | Russ Swan | Mike Boddicker | Jeff Gray | Michael Jackson | | 537 | 553 | -16 |
| 1990-09-08 | @ BOS | 139 | L 2-10 | 68-71 | 5 | 32,680 | Rich DeLucia | Tom Bolton | Tom Bolton | Scott Medvin | | 539 | 563 | -24 |
| 1990-09-09 | @ BOS | 140 | W 3-1 | 69-71 | 4 | 33,923 | Matt Young | Joe Hesketh | Matt Young | Joe Hesketh | Bill Swift | 542 | 564 | -22 |
| 1990-09-10 | vs OAK | 141 | W 5-2 | 70-71 | 4 | 25,129 | Erik Hanson | Bob Welch | Erik Hanson | Bob Welch | Keith Comstock | 547 | 566 | -19 |
| 1990-09-11 | vs OAK | 142 | L 2-10 | 70-72 | 5 | 17,867 | Randy Johnson | Curt Young | Curt Young | Randy Johnson | | 549 | 576 | -27 |
| 1990-09-12 | vs OAK | 143 | L 3-9 | 70-73 | 5 | 14,427 | Mike Gardiner | Scott Sanderson | Scott Sanderson | Mike Gardiner | | 552 | 585 | -33 |
| 1990-09-13 | @ CAL | 144 | L 1-7 | 70-74 | 5 | 21,683 | Rich DeLucia | Chuck Finley | Chuck Finley | Keith Comstock | | 553 | 592 | -39 |
| 1990-09-14 | @ CAL | 145 | L 5-7 | 70-75 | 5 | 34,180 | Matt Young | Kirk McCaskill | Bob McClure | Matt Young | Bryan Harvey | 558 | 599 | -41 |
| 1990-09-15 | @ CAL | 146 | W 7-2 | 71-75 | 5 | 27,948 | Erik Hanson | Jim Abbott | Erik Hanson | Jim Abbott | | 565 | 601 | -36 |
| 1990-09-16 | @ CAL | 147 | W 5-3 | 72-75 | 5 | 30,000 | Randy Johnson | Mark Langston | Bill Swift | Bryan Harvey | Michael Jackson | 570 | 604 | -34 |
| 1990-09-17 | vs TEX | 148 | L 4-10 | 72-76 | 5 | 10,741 | Mike Gardiner | Bobby Witt | Bobby Witt | Mike Gardiner | | 574 | 614 | -40 |
| 1990-09-18 | vs TEX | 149 | W 7-3 | 73-76 | 5 | 7,333 | Rich DeLucia | Charlie Hough | Rich DeLucia | Mike Jeffcoat | | 581 | 617 | -36 |
| 1990-09-19 | vs TEX | 150 | L 5-6 | 73-77 | 5 | 11,580 | Matt Young | Nolan Ryan | John Barfield | Matt Young | Kenny Rogers | 586 | 623 | -37 |
| 1990-09-20 | vs CHA | 151 | W 7-3 | 74-77 | 5 | 7,956 | Erik Hanson | Greg Hibbard | Erik Hanson | Greg Hibbard | | 593 | 626 | -33 |
| 1990-09-21 | vs CHA | 152 | L 4-5 | 74-78 | 5 | 55,679 | Randy Johnson | Eric King | Eric King | Randy Johnson | Bobby Thigpen | 597 | 631 | -34 |
| 1990-09-22 | vs CHA | 153 | L 5-14 | 74-79 | 5 | 16,710 | Mike Gardiner | Melido Perez | Steve Rosenberg | Brent Knackert | Donn Pall | 602 | 645 | -43 |
| 1990-09-23 | vs CHA | 154 | L 1-2 | 74-80 | 5 | 19,666 | Matt Young | Alex Fernandez | Alex Fernandez | Matt Young | Bobby Thigpen | 603 | 647 | -44 |
| 1990-09-25 | @ DET | 155 | L 1-4 | 74-81 | 5 | 11,210 | Rich DeLucia | Walt Terrell | Mike Henneman | Rich DeLucia | | 604 | 651 | -47 |
| 1990-09-26 | @ DET | 156 | W 8-4 | 75-81 | 5 | 11,865 | Erik Hanson | Frank Tanana | Erik Hanson | Frank Tanana | Bill Swift | 612 | 655 | -43 |
| 1990-09-28 | @ CHA | 157 | W 13-4 | 76-81 | 5 | 37,662 | Randy Johnson | Alex Fernandez | Randy Johnson | Alex Fernandez | | 625 | 659 | -34 |
| 1990-09-29 | @ CHA | 158 | L 2-5 | 76-82 | 5 | 42,800 | Matt Young | Eric King | Eric King | Matt Young | Bobby Thigpen | 627 | 664 | -37 |
| 1990-09-30 | @ CHA | 159 | L 1-2 | 76-83 | 5 | 42,849 | Rich DeLucia | Jack McDowell | Jack McDowell | Rich DeLucia | Bobby Thigpen | 628 | 666 | -38 |
| 1990-10-01 | @ MIN | 160 | L 5-7 | 76-84 | 5 | 9,202 | Russ Swan | Kevin Tapani | Kevin Tapani | Russ Swan | Rich Garces | 633 | 673 | -40 |
| 1990-10-02 | @ MIN | 161 | W 3-0 | 77-84 | 5 | 10,091 | Erik Hanson | Paul Abbott | Erik Hanson | Paul Abbott | | 636 | 673 | -37 |
| 1990-10-03 | @ MIN | 162 | L 4-7 | 77-85 | 5 | 9,826 | Randy Johnson | Larry Casian | Larry Casian | Randy Johnson | Rick Aguilera | 640 | 680 | -40 |