(Click on the column title to sort by that column)
| # | Catholics | Population | Percent Catholic | Diocese | Year | Source |
|---|---|---|---|---|---|---|
| 1 | 728,000 | 1,318,000 | 55.24% | Antsirabé | 2004 | ap2005 |
| 2 | 192,035 | 396,774 | 48.40% | Miarinarivo | 2004 | ap2005 |
| 3 | 334,828 | 696,000 | 48.11% | Ambositra | 2004 | ap2005 |
| 4 | 467,476 | 1,153,750 | 40.52% | Fianarantsoa (Archdiocese) | 2004 | ap2005 |
| 5 | 172,189 | 464,211 | 37.09% | Tsiroanomandidy | 2004 | ap2005 |
| 6 | 600,000 | 1,800,000 | 33.33% | Toamasina | 2004 | ap2005 |
| 7 | 761,962 | 2,816,149 | 27.06% | Antananarivo (Archdiocese) | 2004 | ap2005 |
| 8 | 271,275 | 1,459,275 | 18.59% | Ambatondrazaka | 2004 | ap2005 |
| 9 | 56,180 | 310,158 | 18.11% | Ihosy | 2004 | ap2005 |
| 10 | 343,354 | 2,211,809 | 15.52% | Antsiranana (Archdiocese) | 2004 | ap2005 |
| 11 | 110,850 | 739,116 | 15.00% | Fenoarivo Atsinanana | 2004 | ap2005 |
| 12 | 103,700 | 700,000 | 14.81% | Mananjary | 2004 | ap2005 |
| 13 | 142,447 | 992,794 | 14.35% | Mahajanga | 2004 | ap2005 |
| 14 | 100,000 | 860,000 | 11.63% | Tôlagnaro | 2004 | ap2005 |
| 15 | 79,000 | 795,000 | 9.94% | Toliara (Archdiocese) | 2004 | ap2005 |
| 16 | 41,620 | 460,200 | 9.04% | Morondava | 2004 | ap2005 |
| 17 | 90,262 | 1,098,075 | 8.22% | Ambanja | 2004 | ap2005 |
| 18 | 31,206 | 387,263 | 8.06% | Morombe | 2002 | ap2004 |
| 19 | 71,487 | 900,000 | 7.94% | Farafangana | 2004 | ap2005 |
| 20 | 10,400 | 518,451 | 2.01% | Port-Bergé | 2004 | ap2005 |
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