The best selling album in 1991 in Portugal was MCMXC A.D. by ENIGMA.
| Rank | Artist | Album | Released |
| 1 | ENIGMA | MCMXC A.D. | 1990 |
| 2 | R.E.M. | OUT OF TIME | 1991 |
| 3 | BRYAN ADAMS | WAKING UP THE NEIGHBOURS | 1991 |
| 4 | ANGELO BADALAMENTI | TWIN PEAKS (SOUNDTRACK) | 1990 |
| 5 | JUAN LUIS GUERRA | BACHATA ROSA | 1990 |
| 6 | SUPERTRAMP | THE VERY BEST OF SUPERTRAMP | 1990 |
| 7 | THE BEACH BOYS | THE BEACH BOYS COLLECTION | 1990 |
| 8 | QUEEN | INNUENDO | 1991 |
| 9 | RUI VELOSO | MINGOS & OS SAMURAIS | 1990 |
| 10 | SOUNDTRACK | TIETA | 1991 |
Source: AFP