Országos Bajnokság I (men's water polo)
| Current season, competition or edition: 2023–24 Országos Bajnokság I (men's water polo) | |
| Sport | Water Polo |
|---|---|
| Founded | 1904 |
| No. of teams | 14 |
| Country | Hungary |
| Confederation | LEN (Europe) |
| Most recent champion(s) | Ferencváros (26th titles) (2023–24) |
| Most titles | Újpest (26 titles) Ferencváros (26 titles) |
| Broadcaster(s) | M4 Sport |
| Relegation to | Országos Bajnokság I/B |
| Domestic cup(s) | Magyar Kupa |
| International cup(s) | LEN Champions League LEN Euro Cup |
| Official website | waterpolo |
Országos Bajnokság I (English: Nationwide Championship I, commonly abbreviated OB I) is the highest level water polo league for men in Hungary, that is administered and supervised by the Hungarian Water Polo Federation. Since 2009, after signed a four-year sponsorship contract with telecommunications company Vodafone, the competition is officially known as Vodafone OB I.