2005 Washington Nationals season Game log May

| Date_ | Opponent | Score | Loss | Attendance | Record |
|---|---|---|---|---|---|
| May 11 | @ Arizona Diamondbacks | 2-3 | Rauch (1-3) | 21011 | 18-16 |
| May 13 | Chicago Cubs | 3-6 | Ayala (2-2) | 36585 | 18-17 |
| May 14 | Chicago Cubs | 4-3 | Zambrano (3-2) | 42829 | 19-17 |
| May 15 | Chicago Cubs | 5-4 | Bartosh (0-2) | 44103 | 20-17 |
| May 16 | Milwaukee Brewers | 5-2 | Davis (4-5) | 26606 | 21-17 |
| May 17 | Milwaukee Brewers | 2-8 | Vargas (0-1) | 26427 | 21-18 |
| May 18 | Milwaukee Brewers | 1-0 | Capuano (3-3) | 29216 | 22-18 |
| May 19 | Milwaukee Brewers | 3-2 | Santos (1-4) | 30968 | 23-18 |
| May 20 | Toronto Blue Jays | 1-6 | Vargas (0-2) | 17465 | 23-19 |
| May 21 | Toronto Blue Jays | 0-7 | Armas (1-2) | 24518 | 23-20 |
| May 22 | Toronto Blue Jays | 9-2 | Towers (5-2) | 28408 | 24-20 |