(Click on the column title to sort by that column)
| # | Catholics | Population | Percent Catholic | Diocese | Year | Source |
|---|---|---|---|---|---|---|
| 1 | 1,590,150 | 2,340,928 | 67.93% | Montréal (Archdiocese) | 2004 | ap2005 |
| 2 | 1,363,657 | 5,043,085 | 27.04% | Toronto (Archdiocese) | 2004 | ap2005 |
| 3 | 1,076,180 | 1,149,301 | 93.64% | Québec (Archdiocese) | 2004 | ap2005 |
| 4 | 622,138 | 1,944,182 | 32.00% | London | 2004 | ap2005 |
| 5 | 563,094 | 654,066 | 86.09% | Saint-Jean-Longueuil | 2004 | ap2005 |
| 6 | 559,290 | 1,657,084 | 33.75% | Hamilton | 2004 | ap2005 |
| 7 | 407,065 | 419,150 | 97.12% | Saint-Jérôme | 2004 | ap2005 |
| 8 | 400,000 | 1,000,000 | 40.00% | Calgary | 2004 | ap2005 |
| 9 | 396,898 | 2,204,991 | 18.00% | Vancouver (Archdiocese) | 2004 | ap2005 |
| 10 | 392,635 | 812,305 | 48.34% | Ottawa (Archdiocese) | 2004 | ap2005 |
| 11 | 349,614 | 359,844 | 97.16% | Saint-Hyacinthe | 2004 | ap2005 |
| 12 | 341,545 | 1,365,428 | 25.01% | Edmonton (Archdiocese) | 2004 | ap2005 |
| 13 | 291,261 | 316,998 | 91.88% | Sherbrooke (Archdiocese) | 2004 | ap2005 |
| 14 | 258,692 | 262,317 | 98.62% | Chicoutimi | 2004 | ap2005 |
| 15 | 247,999 | 250,715 | 98.92% | Trois Rivières | 2004 | ap2005 |
| 16 | 218,445 | 231,430 | 94.39% | Joliette | 2004 | ap2005 |
| 17 | 206,405 | 373,590 | 55.25% | Sault Sainte Marie | 2004 | ap2005 |
| 18 | 189,895 | 193,865 | 97.95% | Nicolet | 2004 | ap2005 |
| 19 | 185,295 | 232,828 | 79.58% | Valleyfield | 2004 | ap2005 |
| 20 | 155,000 | 540,821 | 28.66% | Halifax (Archdiocese) | 2004 | ap2005 |
| 21 | 155,000 | 667,209 | 23.23% | Winnipeg (Archdiocese) | 2004 | ap2005 |
| 22 | 148,850 | 440,000 | 33.83% | Saint Catharines | 2004 | ap2005 |
| 23 | 144,272 | 148,341 | 97.26% | Rimouski (Archdiocese) | 2004 | ap2005 |
| 24 | 129,905 | 223,824 | 58.04% | Antigonish | 2004 | ap2005 |
| 25 | 120,000 | 392,000 | 30.61% | Regina (Archdiocese) | 2004 | ap2005 |
| 26 | 116,845 | 315,000 | 37.09% | Kingston (Archdiocese) | 2004 | ap2005 |
| 27 | 113,495 | 416,689 | 27.24% | Saint-Boniface (Archdiocese) | 2004 | ap2005 |
| 28 | 112,710 | 280,000 | 40.25% | Saint John, New Brunswick | 2004 | ap2005 |
| 29 | 111,000 | 213,000 | 52.11% | Saint John's, Newfoundland (Archdiocese) | 2004 | ap2005 |
| 30 | 109,634 | 119,634 | 91.64% | Bathurst | 2004 | ap2005 |
| 31 | 108,000 | 208,500 | 51.80% | Moncton (Archdiocese) | 2004 | ap2005 |
| 32 | 99,785 | 396,622 | 25.16% | Peterborough | 2004 | ap2005 |
| 33 | 94,465 | 693,496 | 13.62% | Victoria | 2004 | ap2005 |
| 34 | 93,413 | 99,474 | 93.91% | Amos | 2004 | ap2005 |
| 35 | 89,768 | 92,464 | 97.08% | Sainte-Anne-de-la-Pocatière | 2004 | ap2005 |
| 36 | 89,232 | 90,907 | 98.16% | Baie-Comeau | 2004 | ap2005 |
| 37 | 86,645 | 245,000 | 35.37% | Saskatoon | 2004 | ap2005 |
| 38 | 84,671 | 96,924 | 87.36% | Gaspé | 2004 | ap2005 |
| 39 | 82,074 | 92,218 | 89.00% | Mont-Laurier | 2004 | ap2005 |
| 40 | 80,000 | Saint-Maron de Montréal (Maronite) (Eparchy) | 2004 | ap2005 | ||
| 41 | 73,780 | 240,000 | 30.74% | Thunder Bay | 2004 | ap2005 |
| 42 | 65,650 | 132,000 | 49.73% | Pembroke | 2004 | ap2005 |
| 43 | 65,000 | 365,000 | 17.81% | Nelson | 2004 | ap2005 |
| 44 | 61,680 | 140,263 | 43.97% | Charlottetown | 2004 | ap2005 |
| 45 | 58,901 | 60,503 | 97.35% | Rouyn-Noranda | 2004 | ap2005 |
| 46 | 56,050 | 87,383 | 64.14% | Alexandria-Cornwall | 2004 | ap2005 |
| 47 | 53,365 | 129,315 | 41.27% | Saint Paul in Alberta | 2004 | ap2005 |
| 48 | 51,200 | 234,416 | 21.84% | Prince George | 2004 | ap2005 |
| 49 | 49,839 | 52,536 | 94.87% | Edmundston | 2004 | ap2005 |
| 50 | 48,900 | 92,500 | 52.86% | Timmins | 2004 | ap2005 |
| 51 | 47,000 | 400,000 | 11.75% | Kamloops | 2004 | ap2005 |
| 52 | 44,470 | 114,760 | 38.75% | Grouard-McLennan (Archdiocese) | 2004 | ap2005 |
| 53 | 43,000 | Saint-Sauveur de Montréal (Melkite) (Eparchy) | 2004 | ap2005 | ||
| 54 | 42,218 | 110,025 | 38.37% | Keewatin-Le Pas (Archdiocese) | 2004 | ap2005 |
| 55 | 40,732 | 184,000 | 22.14% | Prince-Albert | 2004 | ap2005 |
| 56 | 36,910 | Toronto (Ukrainian) (Eparchy) | 2004 | ap2005 | ||
| 57 | 36,774 | 181,978 | 20.21% | Grand Falls | 2004 | ap2005 |
| 58 | 36,000 | 143,261 | 25.13% | Yarmouth | 2004 | ap2005 |
| 59 | 29,740 | Winnipeg (Ukrainian) (Archeparchy) | 2004 | ap2005 | ||
| 60 | 29,563 | 38,336 | 77.12% | Hearst | 2004 | ap2005 |
| 61 | 28,540 | 42,040 | 67.89% | Mackenzie-Fort Smith | 2004 | ap2005 |
| 62 | 27,201 | 66,507 | 40.90% | Saint George's | 2004 | ap2005 |
| 63 | 26,250 | Edmonton (Ukrainian) (Eparchy) | 2004 | ap2005 | ||
| 64 | 14,542 | 43,924 | 33.11% | Labrador City-Schefferville | 2004 | ap2005 |
| 65 | 12,700 | Saskatoon (Ukrainian) (Eparchy) | 2004 | ap2005 | ||
| 66 | 9,175 | 35,614 | 25.76% | Whitehorse | 2003 | ap2005 |
| 67 | 7,950 | 27,500 | 28.91% | Churchill-Baie d'Hudson | 2004 | ap2005 |
| 68 | 7,835 | New Westminister (Ukrainian) (Eparchy) | 2004 | ap2005 | ||
| 69 | 6,100 | 22,200 | 27.48% | Moosonee | 2004 | ap2005 |
| 70 | 5,000 | Saints Cyril and Methodius of Toronto (Slovakian) (Eparchy) | 2004 | ap2005 |
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