The River Om (in Russian: Омь) is a River plains of Western Siberia, in Russia, and a Affluent of the Irtych. Long of 1091 km, the river a Bassin pouring 52  drains; 400 km ² and have a maximum flow of 814  m ³ /s. Om occurs in the Marais of Vassiougan, with the limit of the Oblast S of Novossibirsk and Omsk. It runs out towards the west before being thrown in Irtych. The town of Omsk is with the junction of Om and Irtych. Its principal affluents are the rivers Icha, Ougourmanka, Ouzakla, Kama and Tartas.

Om sprinkles the towns of Barabinsk, Kalatchinsk, Kouïbychev and Omsk.