(Click on the column title to sort by that column)
| # | Catholics | Population | Percent Catholic | Diocese | Year | Source |
|---|---|---|---|---|---|---|
| 1 | 167,850 | 173,221 | 96.90% | Tulcán | 2004 | ap2005 |
| 2 | 330,000 | 344,000 | 95.93% | Ibarra | 2004 | ap2005 |
| 3 | 117,100 | 122,300 | 95.75% | Zamora en Ecuador (Vicariate Apostolic) | 2004 | ap2005 |
| 4 | 595,388 | 626,250 | 95.07% | Cuenca (Archdiocese) | 2004 | ap2005 |
| 5 | 200,556 | 211,112 | 95.00% | Azogues | 2004 | ap2005 |
| 6 | 523,442 | 552,031 | 94.82% | Loja | 2004 | ap2005 |
| 7 | 485,000 | 512,000 | 94.73% | Machala | 2004 | ap2005 |
| 8 | 1,091,143 | 1,186,025 | 92.00% | Portoviejo (Archdiocese) | 2004 | ap2005 |
| 9 | 164,341 | 181,011 | 90.79% | Guaranda | 2004 | ap2005 |
| 10 | 1,893,295 | 2,103,661 | 90.00% | Quito (Archdiocese) | 2004 | ap2005 |
| 11 | 55,068 | 61,779 | 89.14% | Puyo (Vicariate Apostolic) | 2004 | ap2005 |
| 12 | 434,105 | 490,000 | 88.59% | Esmeraldas (Vicariate Apostolic) | 2004 | ap2005 |
| 13 | 3,000,000 | 3,400,000 | 88.24% | Guayaquil (Archdiocese) | 2004 | ap2005 |
| 14 | 425,310 | 486,193 | 87.48% | Ambato | 2004 | ap2005 |
| 15 | 635,100 | 730,000 | 87.00% | Babahoyo | 2004 | ap2005 |
| 16 | 100,000 | 115,412 | 86.65% | Méndez (Vicariate Apostolic) | 2004 | ap2005 |
| 17 | 600,000 | 700,000 | 85.71% | Santo Domingo de los Colorados | 2004 | ap2005 |
| 18 | 300,000 | 351,000 | 85.47% | Latacunga | 2004 | ap2005 |
| 19 | 109,646 | 128,995 | 85.00% | San Miguel de Sucumbíos (Vicariate Apostolic) | 2004 | ap2005 |
| 20 | 100,600 | 120,000 | 83.83% | Aguarico (Vicariate Apostolic) | 2004 | ap2005 |
| 21 | 82,923 | 99,242 | 83.56% | Napo (Vicariate Apostolic) | 2004 | ap2005 |
| 22 | 330,000 | 403,185 | 81.85% | Riobamba | 2004 | ap2005 |
| 23 | 14,600 | 19,000 | 76.84% | Galápagos (Prefecture Apostolic) | 2004 | ap2005 |
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