| Event: | Women's marathon |
| Win Label: | Winning time |
The women's marathon event at the 2003 Pan American Games took place on Saturday, 9 August 2003. Brazil's Márcia Narloch won the title, defeating title defender Érika Olivera from Chile.
| 2:15:25 | 13 April 2003 | ||||
| 2:37:41 | 25 July 1999 |  Winnipeg, Canada |
| Rank | Athlete | Time | |
|---|---|---|---|
| 1 | 2:39:54 | ||
| 2 | 2:42:55 | ||
| 3 | 2:44:52 | ||
| 4 | 2:47:40 | ||
| 5 | 2:51:58 | ||
| 6 | 2:53:03 | ||
| 7 | 2:53:56 | ||
| 8 | 2:54:16 | ||
| 9 | 2:55:14 | ||
| 10 | 2:59:05 | ||
| 11 | 3:04:12 | ||
| 12 | 3:04:47 | ||
| 13 | 3:35:02 | ||
| - | DNF | ||
| - | DNF |