| Competition: | OB I |
| Season: | 2004–2005 |
| Winners: | Honvéd |
| Continentalcup1: | Euroleague |
| Continentalcup1 Qualifiers: | Honvéd Vasas Szeged |
| Continentalcup2: | LEN Cup |
| Continentalcup2 Qualifiers: | Eger Ferencváros |
| Prevseason: | 2003–04 |
| Nextseason: | 2005–06 |
2004–05 Országos Bajnokság I (men's water polo) was the 99th water polo championship in Hungary.
| Team | M | W | D | L | G+ | G− | P | |
|---|---|---|---|---|---|---|---|---|
| 1. | Domino-Bp. Honvéd | 22 | 21 | 0 | 1 | 306 | 110 | 42 |
| 2. | TEVA-Vasas SC-Plaket | 22 | 19 | 0 | 3 | 234 | 120 | 38 |
| 3. | Brendon-ZF-Egri VK | 22 | 19 | 0 | 3 | 236 | 119 | 38 |
| 4. | Szeged-Beton VE | 22 | 14 | 1 | 7 | 173 | 139 | 29 |
| 5. | Betonút-Ferencvárosi TC | 22 | 14 | 0 | 8 | 195 | 123 | 28 |
| 6. | Újpesti TE-VB Leasing | 22 | 13 | 0 | 9 | 188 | 181 | 26 |
| 7. | Legrand-Szentesi VK | 22 | 8 | 1 | 13 | 166 | 205 | 17 |
| 8. | BVSC-Turbo | 22 | 7 | 1 | 14 | 169 | 196 | 15 |
| 9. | OSC-British Knights | 22 | 6 | 2 | 14 | 139 | 227 | 14 |
| 10. | Szolnoki VSC | 22 | 5 | 3 | 14 | 140 | 206 | 13 |
| 11. | Neptun VSC | 22 | 2 | 0 | 20 | 107 | 260 | 4 |
| 12. | Szent István Egyetem | 22 | 0 | 0 | 22 | 93 | 260 | 0 |
| Championship Playoff | ||
| European competition Playoff | ||
| Relegation Playoff |