| Competition: | OB I |
| Season: | 2009–10 |
| Winners: | Vasas (17th title) |
| Continentalcup1: | Euroleague |
| Continentalcup1 Qualifiers: | TEVA-VasasPlaket ZF-Eger Szeged Beton |
| Continentalcup2: | LEN Cup |
| Continentalcup2 Qualifiers: | FTC-Fisher Klíma Domino Honvéd |
| League Topscorer: | dr. Tamás Molnár (69 goals) |
| Prevseason: | 2008–09 |
| Nextseason: | 2010–11 |
2009–10 Országos Bajnokság I (men's water polo) (known as the Vodafone férfi OB I osztályú Országos Bajnokság for sponsorship reasons) was the 104th water polo championship in Hungary.
| Team | M | Gy | D | V | G+ | G− | P | |
|---|---|---|---|---|---|---|---|---|
| 1. | ZF-Egri VK | 20 | 17 | 1 | 2 | 221 | 141 | 52 |
| 2. | TEVA-Vasas SC-Plaket | 20 | 16 | 1 | 3 | 273 | 126 | 49 |
| 3. | Szeged-Beton VE | 20 | 14 | 3 | 3 | 204 | 139 | 45 |
| 4. | Ferencvárosi TC | 20 | 13 | 1 | 6 | 182 | 155 | 40 |
| 5. | Domino-Bp. Honvéd | 20 | 12 | 2 | 6 | 199 | 145 | 38 |
| 6. | Szolnoki Főiskola VSC-Közgép | 20 | 9 | 4 | 7 | 179 | 161 | 31 |
| 7. | BVSC-Zugló | 20 | 7 | 1 | 12 | 161 | 219 | 22 |
| 8. | Uniqa-Újpesti TE | 20 | 5 | 1 | 14 | 131 | 202 | 16 |
| 9. | Pécsi Vízmű-Pécsi VSK | 20 | 3 | 3 | 14 | 157 | 222 | 12 |
| 10. | OSC | 20 | 3 | 2 | 15 | 147 | 233 | 11 |
| 11. | Szentesi VK | 20 | 1 | 1 | 18 | 125 | 236 | 4 |
| Championship Playoff | ||
| European competition Playoff | ||
| Relegation Playoff |
| Team | M | W | D | L | G+ | G− | P | BP | |
|---|---|---|---|---|---|---|---|---|---|
| 5. | Domino-Bp. Honvéd | 6 | 6 | 0 | 0 | 68 | 37 | 30 | 18 |
| 6. | Szolnoki Főiskola VSC-Közgép | 6 | 3 | 2 | 1 | 51 | 38 | 19 | 11 |
| 7. | BVSC-Zugló | 6 | 1 | 1 | 4 | 47 | 62 | 10 | 4 |
| 8. | Uniqa-Újpesti TE | 6 | 1 | 0 | 5 | 46 | 75 | 6 | 3 |
| LEN Cup qualification |
| Team | M | W | D | L | G+ | G− | P | BP | |
|---|---|---|---|---|---|---|---|---|---|
| 9. | Pécsi Vízmű-Pécsi VSK | 4 | 2 | 1 | 1 | 43 | 37 | 19 | 7 |
| 10. | OSC | 4 | 2 | 2 | 0 | 41 | 31 | 17 | 8 |
| 11. | Szentesi VK | 4 | 0 | 1 | 3 | 31 | 47 | 7 | 1 |
| Relegation |
| width=10px bgcolor=#ccffcc | Qualified for the 2010–11 LEN Euroleague | ||
| width=10px bgcolor=#bbebff | Qualified for the 2010–11 LEN Cup |
| 1 Viktor Nagy, 2 Ádám Decker, 3 Bence Fülöp, 4 Gergely Katonás 5 Norbert Hosnyánszky, 6 Viktor Vörös, 7 Róbert Kovács Csatlós, 8 Krisztián Létay 9 Dénes Varga, 10 Dániel Varga, 11 Gábor Kis 12 Bálint Takács, 13 Dávid Hőna, 14 György Jónás | |
| Head coach | |
| László Földi |