(Click on the column title to sort by that column)
| # | Catholics | Population | Percent Catholic | Diocese | Year | Source |
|---|---|---|---|---|---|---|
| 1 | 2,500,000 | 2,729,610 | 91.59% | Buenos Aires (Archdiocese) | 2004 | ap2005 |
| 2 | 1,797,300 | 1,997,243 | 89.99% | Córdoba (Archdiocese) | 2004 | ap2005 |
| 3 | 1,771,037 | 2,061,548 | 85.91% | Lomas de Zamora | 2004 | ap2005 |
| 4 | 1,501,620 | 1,700,000 | 88.33% | Rosario (Archdiocese) | 2004 | ap2005 |
| 5 | 1,145,000 | 1,373,000 | 83.39% | Mendoza (Archdiocese) | 2004 | ap2005 |
| 6 | 1,000,000 | 1,200,000 | 83.33% | Quilmes | 2004 | ap2005 |
| 7 | 986,000 | 1,010,000 | 97.62% | San Isidro | 2004 | ap2005 |
| 8 | 911,849 | 1,035,017 | 88.10% | Tucumán (Archdiocese) | 2004 | ap2005 |
| 9 | 865,820 | 930,991 | 93.00% | Corrientes (Archdiocese) | 2004 | ap2005 |
| 10 | 810,000 | 895,000 | 90.50% | Santa Fe de la Vera Cruz (Archdiocese) | 2004 | ap2005 |
| 11 | 810,000 | 900,000 | 90.00% | San Justo | 2004 | ap2005 |
| 12 | 800,000 | 835,200 | 95.79% | San Miguel | 2004 | ap2005 |
| 13 | 701,737 | 850,591 | 82.50% | Merlo-Moreno | 2004 | ap2005 |
| 14 | 700,000 | San Charbel en Buenos Aires (Maronite) (Eparchy) | 2004 | ap2005 | ||
| 15 | 689,300 | 712,000 | 96.81% | Mercedes-Luján (Archdiocese) | 2004 | ap2005 |
| 16 | 677,678 | 752,976 | 90.00% | Salta (Archdiocese) | 2004 | ap2005 |
| 17 | 662,186 | 827,732 | 80.00% | Mar del Plata | 2004 | ap2005 |
| 18 | 637,500 | 750,000 | 85.00% | La Plata (Archdiocese) | 2004 | ap2005 |
| 19 | 630,000 | 700,000 | 90.00% | Gregorio de Laferrere | 2004 | ap2005 |
| 20 | 600,000 | 660,500 | 90.84% | Zárate-Campana | 2004 | ap2005 |
| 21 | 595,000 | 700,000 | 85.00% | Bahía Blanca (Archdiocese) | 2004 | ap2005 |
| 22 | 586,117 | 651,241 | 90.00% | Santiago del Estero | 2004 | ap2005 |
| 23 | 580,500 | 628,560 | 92.35% | San Juan de Cuyo (Archdiocese) | 2004 | ap2005 |
| 24 | 558,950 | 798,500 | 70.00% | Avellaneda-Lanús | 2004 | ap2005 |
| 25 | 552,890 | 769,000 | 71.90% | Posadas | 2004 | ap2005 |
| 26 | 518,490 | 740,700 | 70.00% | San Martín | 2004 | ap2005 |
| 27 | 511,000 | 655,000 | 78.02% | Morón | 2004 | ap2005 |
| 28 | 504,000 | 560,000 | 90.00% | Jujuy | 2004 | ap2005 |
| 29 | 465,000 | 550,000 | 84.55% | Formosa | 2004 | ap2005 |
| 30 | 452,250 | 502,500 | 90.00% | Paraná (Archdiocese) | 2004 | ap2005 |
| 31 | 450,000 | 540,000 | 83.33% | Resistencia (Archdiocese) | 2004 | ap2005 |
| 32 | 435,035 | 494,358 | 88.00% | Neuquén | 2004 | ap2005 |
| 33 | 412,714 | 463,723 | 89.00% | Azul | 2004 | ap2005 |
| 34 | 410,000 | 480,000 | 85.42% | San Roque de Presidencia Roque Sáenz Peña | 2004 | ap2005 |
| 35 | 391,400 | 412,000 | 95.00% | Villa de la Concepción del Río Cuarto | 2004 | ap2005 |
| 36 | 390,000 | 427,000 | 91.33% | San Nicolás de los Arroyos | 2004 | ap2005 |
| 37 | 347,496 | 370,000 | 93.92% | San Luis | 2004 | ap2005 |
| 38 | 345,000 | 412,912 | 83.55% | Comodoro Rivadavia | 2004 | ap2005 |
| 39 | 343,977 | 382,196 | 90.00% | Nueve de Julio | 2004 | ap2005 |
| 40 | 323,490 | 330,092 | 98.00% | Catamarca | 2004 | ap2005 |
| 41 | 313,194 | 351,903 | 89.00% | Chascomús | 2004 | ap2005 |
| 42 | 308,000 | 375,000 | 82.13% | Villa María | 2004 | ap2005 |
| 43 | 295,545 | 347,700 | 85.00% | Alto Valle del Río Negro | 2004 | ap2005 |
| 44 | 288,000 | 320,450 | 89.87% | Gualeguaychú | 2004 | ap2005 |
| 45 | 280,000 | 321,100 | 87.20% | Orán | 2004 | ap2005 |
| 46 | 265,350 | 305,000 | 87.00% | La Rioja | 2004 | ap2005 |
| 47 | 265,000 | 275,000 | 96.36% | Concordia | 2004 | ap2005 |
| 48 | 248,348 | 299,294 | 82.98% | Santa Rosa | 2004 | ap2005 |
| 49 | 233,000 | 265,000 | 87.92% | Reconquista | 2004 | ap2005 |
| 50 | 230,000 | 255,008 | 90.19% | Rafaela | 2004 | ap2005 |
| 51 | 220,500 | 315,000 | 70.00% | Concepción | 2004 | ap2005 |
| 52 | 212,898 | 236,322 | 90.09% | Goya | 2004 | ap2005 |
| 53 | 210,000 | 300,000 | 70.00% | Puerto Iguazú | 2004 | ap2005 |
| 54 | 205,820 | 210,000 | 98.01% | San Francisco | 2004 | ap2005 |
| 55 | 200,000 | 300,000 | 66.67% | Río Gallegos | 2004 | ap2005 |
| 56 | 200,000 | 210,000 | 95.24% | Venado Tuerto | 2004 | ap2005 |
| 57 | 195,500 | 230,000 | 85.00% | San Rafael | 2004 | ap2005 |
| 58 | 144,431 | 155,191 | 93.07% | Cruz del Eje | 2004 | ap2005 |
| 59 | 140,499 | 156,109 | 90.00% | Santo Tomé | 2004 | ap2005 |
| 60 | 130,000 | Santa María del Patrocinio en Buenos Aires (Ukrainian) (Eparchy) | 2004 | ap2005 | ||
| 61 | 120,721 | 138,920 | 86.90% | Añatuya | 2004 | ap2005 |
| 62 | 112,500 | 149,000 | 75.50% | San Carlos de Bariloche | 2004 | ap2005 |
| 63 | 104,674 | 132,840 | 78.80% | Viedma | 2004 | ap2005 |
| 64 | 80,000 | 95,000 | 84.21% | Humahuaca (Territorial Prelature) | 2004 | ap2005 |
| 65 | 53,534 | 59,482 | 90.00% | Deán Funes (Territorial Prelature) | 2004 | ap2005 |
| 66 | 53,194 | 54,625 | 97.38% | Cafayate (Territorial Prelature) | 2004 | ap2005 |
| 67 | 16,000 | San Gregorio de Narek en Buenos Aires (Armenian) (Eparchy) | 2004 | ap2005 | ||
| 68 | 2,000 | Argentina, Faithful of the Oriental Rites (Ordinariate) | 2004 | ap2005 |
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