Portuguese legislative election, 1991 Opinion Polling 116 seats needed for a majority

| Date_Released | Polling_institute | Social_Democratic | Socialist | Green_Communist | Democratic_and_Social_Centre | Lead_ |
|---|---|---|---|---|---|---|
| September 28, 1991 | Euroteste | 46.0% | 37.0% | 9.7% | 3.9% | 9.0% |
| September 28, 1991 | Euroexpansão | 44.0% | 33.0% | 9.0% | 6.0% | 11.0% |
| September 27, 1991 | Marktest | 43.1% | 32.8% | 7.7% | 4.6% | 10.3% |
| September 27, 1991 | Pluriteste | 41.2% | 34.7% | 8.4% | 8.1% | 6.5% |
| September 20, 1991 | Euroteste | 45.6% | 35.5% | 10.0% | 4.4% | 10.1% |
| September 20, 1991 | Marktest | 41.9% | 31.9% | 7.3% | 4.4% | 10.0% |
| September 16, 1991 | Pluriteste | 39.2% | 26.6% | 6.2% | 6.0% | 12.6% |
| September 16, 1991 | Euroteste | 45.1% | 34.5% | 10.2% | 5.2% | 10.6% |
| September 14, 1991 | Norma | 45.0% | 37.5% | 11.2% | 3.5% | 7.5% |
| August 28, 1991 | Euroexpansão/Marktest | 35.3% | 36.8% | 8.7% | 4.9% | 1.5% |
| August 4, 1991 | Euroteste/JN | 47.5% | 37.8% | 12.3% | 8.2% | 7.7% |
| July 19, 1987 | 1987 election | 50.2% 148 seats | 22.2% 60 seats | 12.1% 31 seats | 4.4% 4 seats | 28.0% |