| Date | Liberal | Conservative | NDP | Green | Other | Pollster |
|---|---|---|---|---|---|---|
| 8/22/2005 | 45 | 28 | 21 | 6 | — | Ipsos-Reid |
| 8/15/2005 | 45 | 29 | 19 | 6 | — | SES Research |
| 8/7/2005 | 41 | 33 | 17 | 9 | — | Strategic Counsel |
| 7/28/2005 | 42 | 33 | 20 | — | 5 | Environics |
| 7/25/2005 | 46 | 27 | 21 | — | — | Decima |
| 7/8/2005 | 45 | 34 | 17 | — | — | Pollara |
| 6/28/2005 | 42 | 30 | 21 | 5 | — | Ipsos-Reid |
| 6/23/2005 | 44 | 28 | 22 | — | — | Decima |
| 6/20/2005 | 44 | 31 | 16 | 7 | — | Ipsos-Reid |
| 6/11/2005 | 41 | 31 | 19 | — | — | Strategic Counsel |
| 6/8/2005 | 48 | 22 | 24 | — | 6 | Decima |
| 5/28/2005 | 45 | 29 | 24 | — | 3 | Decima |
| 5/26/2005 | 46 | 29 | 19 | 5 | 2 | Leger |
| 5/20/2005 | 46 | 31 | 17 | 5 | — | Ipsos-Reid |
| 5/19/2005 | 45 | 30 | — | — | — | Ekos |
| 5/18/2005 | 43 | 30 | 21 | 6 | — | Strategic Counsel |
| 5/17/2005 | 40 | 32 | 24 | 4 | — | Environics |
| 5/17/2005 | 40 | 34 | 21 | — | — | Decima |
Source: Poll Results: Ontario, Nodice.