(Click on the column title to sort by that column)
| # | Catholics | Population | Percent Catholic | Diocese | Year | Source |
|---|---|---|---|---|---|---|
| 1 | 248,923 | 250,541 | 99.35% | Portalegre-Castelo Branco | 2004 | ap2005 |
| 2 | 147,339 | 148,830 | 99.00% | Bragança-Miranda | 2004 | ap2005 |
| 3 | 237,700 | 240,900 | 98.67% | Vila Real | 2004 | ap2005 |
| 4 | 159,758 | 162,297 | 98.44% | Lamego | 2004 | ap2005 |
| 5 | 245,650 | 250,275 | 98.15% | Viana do Castelo | 2004 | ap2005 |
| 6 | 945,000 | 965,400 | 97.89% | Braga (Archdiocese) | 2004 | ap2005 |
| 7 | 255,000 | 265,000 | 96.23% | Leiria-Fátima | 2004 | ap2005 |
| 8 | 250,000 | 260,000 | 96.15% | Guarda | 2004 | ap2005 |
| 9 | 280,000 | 292,000 | 95.89% | Funchal | 2004 | ap2005 |
| 10 | 270,463 | 284,698 | 95.00% | Viseu | 2004 | ap2005 |
| 11 | 238,425 | 257,380 | 92.64% | Angra | 2004 | ap2005 |
| 12 | 1,869,826 | 2,064,813 | 90.56% | Porto | 2004 | ap2005 |
| 13 | 508,000 | 565,000 | 89.91% | Coimbra | 2004 | ap2005 |
| 14 | 250,000 | 285,000 | 87.72% | Santarém | 2004 | ap2005 |
| 15 | 270,000 | 309,495 | 87.24% | Aveiro | 2004 | ap2005 |
| 16 | 340,000 | 391,819 | 86.77% | Faro | 2004 | ap2005 |
| 17 | 1,966,782 | 2,313,861 | 85.00% | Lisboa (Archdiocese) | 2004 | ap2005 |
| 18 | 246,325 | 290,400 | 84.82% | Évora (Archdiocese) | 2004 | ap2005 |
| 19 | 550,000 | 650,000 | 84.62% | Setúbal | 2004 | ap2005 |
| 20 | 184,194 | 220,794 | 83.42% | Beja | 2004 | ap2005 |
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