1990–91 Országos Bajnokság I (men's water polo) was the 85th water polo championship in Hungary.

First stage #TeamMWDLG+G−P1.Újpesti TE222200324201442.Szentesi SC221615326261333.Tungsram SC221615325222334.Ferencvárosi TC-Törley221345331271305.Vasas SC221138298279256.Szeged SC2210111286262217.Eger SE228311263283198.BVSC228311251270199.Szolnoki Vízügy2273122722861710.OSC-Boniper2271142662961511.Bp. Spartacus224018275360812.Tatabányai Bányász2200222274530

Championship Playoff Pld - Played; W - Won; L - Lost; PF - Points for; PA - Points against; Diff - Difference; Pts - Points.

Championship Playoff

OB I 1990–91Champions Újpest23rd Title

Sources Gyarmati Dezső: Aranykor (Hérodotosz Könyvkiadó és Értékesítő Bt., Budapest, 2002.)