(Click on the column title to sort by that column)
| # | Catholics | Population | Percent Catholic | Diocese | Year | Source |
|---|---|---|---|---|---|---|
| 1 | 1,247,150 | 10,207,295 | 12.22% | Seoul (Archdiocese) | 2004 | ap2005 |
| 2 | 58,512 | 553,864 | 10.56% | Cheju | 2004 | ap2005 |
| 3 | 375,313 | 3,753,748 | 10.00% | Incheon {Inch'on} | 2004 | ap2005 |
| 4 | 127,995 | 1,312,162 | 9.75% | Cheongju {Ch'ongju} | 2003 | ap2004 |
| 5 | 599,044 | 6,446,903 | 9.29% | Suwon | 2004 | ap2005 |
| 6 | 402,958 | 4,466,810 | 9.02% | Daegu {Taegu} (Archdiocese) | 2004 | ap2005 |
| 7 | 301,448 | 3,425,105 | 8.80% | Kwangju (Archdiocese) | 2004 | ap2005 |
| 8 | 163,933 | 1,962,867 | 8.35% | Jeonju {Chonju, Jeon Ju} | 2004 | ap2005 |
| 9 | 161,872 | 2,311,858 | 7.00% | Uijongbu | 2004 | ap2005 |
| 10 | 379,030 | 5,437,906 | 6.97% | Pusan | 2004 | ap2005 |
| 11 | 62,447 | 901,233 | 6.93% | Wonju | 2004 | ap2005 |
| 12 | 214,788 | 3,357,778 | 6.40% | Daejeon {Taejon} | 2004 | ap2005 |
| 13 | 72,295 | 1,144,930 | 6.31% | Ch'unch'on | 2004 | ap2005 |
| 14 | 149,354 | 2,489,945 | 6.00% | Masan | 2004 | ap2005 |
| 15 | 44,666 | 846,476 | 5.28% | Andong | 2004 | ap2005 |
| 16 | 24,996 | 800,000 | 3.12% | Hamhung | 1960 | ap2002 |
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