1998 Seattle Mariners season Game log September

| Date_ | Opponent | Score | Loss | Attendance | Record |
|---|---|---|---|---|---|
| September 1 | @ Boston Red Sox | 7-3 | Lowe (3-8) | 28150 | 63-74 |
| September 2 | @ Boston Red Sox | 3-7 | Ayala (1-10) | 25813 | 63-75 |
| September 4 | Baltimore Orioles | 1-10 | Spoljaric (4-4) | 27404 | 63-76 |
| September 5 | Baltimore Orioles | 6-5 | Benitez (5-4) | 43831 | 64-76 |
| September 6 | Baltimore Orioles | 2-5 | Fassero (10-12) | 30285 | 64-77 |
| September 7 | Baltimore Orioles | 11-1 | Drabek (6-11) | 24229 | 65-77 |
| September 8 | Tampa Bay Devil Rays | 0-10 | Suzuki (0-1) | 20679 | 65-78 |
| September 9 | Tampa Bay Devil Rays | 5-2 | Arrojo (13-12) | 22256 | 66-78 |
| September 11 | @ Kansas City Royals | 6-3 | Barber (2-3) | DH | 67-78 |