(Click on the column title to sort by that column)
| # | Catholics | Population | Percent Catholic | Diocese | Year | Source |
|---|---|---|---|---|---|---|
| 1 | 1,600,000 | 2,500,000 | 64.00% | Mechelen-Brussel {Malines-Brussels} (Archdiocese) | 2004 | ap2005 |
| 2 | 1,281,702 | 1,454,396 | 88.13% | Antwerpen {Antwerp} | 2004 | ap2005 |
| 3 | 1,025,000 | 1,133,931 | 90.39% | Brugge {Bruges} | 2004 | ap2005 |
| 4 | 1,000,000 | 1,400,000 | 71.43% | Gent {Ghent, Gand} | 2004 | ap2005 |
| 5 | 900,000 | 1,279,467 | 70.34% | Tournai {Doornik} | 2004 | ap2005 |
| 6 | 719,000 | 803,892 | 89.44% | Hasselt | 2004 | ap2005 |
| 7 | 700,000 | 1,023,506 | 68.39% | Liège | 2004 | ap2005 |
| 8 | 550,000 | 700,000 | 78.57% | Namur {Namen} | 2004 | ap2005 |
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