The article studies different etymological explanations of the Ural hydronym Serga that names two different rivers: a tributary of the Ufa river and a tributary of the Sylva river. The author points out that both hydronyms relate to the area of historical contacts of various ethnic groups, which complicates the etymological analysis of the name. The article critically observes the existing etymological hypotheses that link the Ural hydronym with a number of Turkic and Finno-Ugric lexemes. The author argues that all these hypotheses, advanced mainly by regional ethnographers, are insuffi cient either from historical, linguistic or geographical point of view. The article suggests new etymological versions for the word Serga, one of them being based on the possible attraction of the Turkic *śü rü ɣ, śərə, śørə etc. ‘ring', the other — on its connection with the Tatar säriğ ‘quick'.