| Competition: | OB I |
| Season: | 1999–2000 |
| Winners: | Ferencváros |
| Prevseason: | 1998–99 |
| Nextseason: | 2000–01 |
1999–2000 Országos Bajnokság I (men's water polo) was the 94th water polo championship in Hungary.
| Team | M | W | D | L | G+ | G− | P | Comments | |
|---|---|---|---|---|---|---|---|---|---|
| 1. | BVSC-Brendon | 18 | 16 | 1 | 1 | 201 | 110 | 33 | |
| 2. | Ferencvárosi TC-Thomas Jeans | 18 | 15 | 1 | 2 | 173 | 104 | 31 | |
| 3. | Bp. Honvéd-Domino | 18 | 13 | 0 | 5 | 196 | 132 | 26 | |
| 4. | Vasas SC-Plaket | 18 | 12 | 2 | 4 | 177 | 137 | 26 | |
| 5. | Újpesti TE-Santal-Taxi2000 | 18 | 8 | 4 | 6 | 155 | 135 | 20 | |
| 6. | Kontavill-Szentesi VK | 18 | 6 | 1 | 11 | 126 | 167 | 13 | |
| 7. | ÚVMK BauSystem-Eger | 18 | 5 | 3 | 10 | 128 | 149 | 13 | |
| 8. | Csanádi Árpád KSI | 18 | 3 | 1 | 14 | 116 | 181 | 7 | |
| 9. | Szolnoki VSC | 18 | 3 | 1 | 14 | 120 | 200 | 7 | |
| 10. | BEAC | 18 | 1 | 2 | 15 | 111 | 188 | 2 | deducted 2 points |
| Championship Playoff |
| width=10px bgcolor=#ccffcc | Qualified for the 2000–01 LEN Champions League | ||
| width=10px bgcolor=#fffa00 | Qualified for the 2000–01 LEN Cup Winners' Cup | ||
| width=10px bgcolor=#bbebff | Qualified for the 2000–01 LEN Cup | ||
| width=10px bgcolor=#ffcccc | Relegation to the 2000–01 OB I/B |
| Zoltán Kósz, Bulcsú Székely, Attila Takács, Márk Matajsz, Csaba Kiss, Máté Hesz, Péter Tiba, Balázs Nyéki, Zsolt Vogel, Ádám Steinmetz, Attila Takács, Tamás Haufe, Norbert Hosnyánszky | |
| Head coach | |
| Lajos Vad |