In the article, an attempt has been made, of analyzing — on the basis of the institutional rational choice conception — distinctions in regional electoral institutions’ structures. Proceeding from the said conception, the author proposes a theoretical model within which these distinctions are accounted for by specific features of the corresponding regions’ political regimes. While checking — against the materials of the 2002 to 2003 electoral reform — the hypotheses advanced, he manages to elicit a fairly high degree of correlation between specific features of regional regimes and the electoral institutions established in the course of the reform. At the same time he also detects a number of “divergencies” from the theoretical model, which are indicative of a need to search for additional factors influencing political process.