The article evaluates the legislative effectiveness of parliamentarians in Russia. The author seeks to find answers to the question: what factors determine the legislative effectiveness of deputies? The article presents the results of assessing the impact of membership in the parliamentary majority party, formal status in the internal parliamentary hierarchy, work experience in legislatures, as well as legal education on legislative success. The study is grounded on the data on the "effectiveness" of deputies of two regional parliaments - St. Petersburg and the Kirov region. The work is based on regression analysis. The results of the study show that membership in the majority party, a position of a chairman of the committee or a leader of the majority party, as well as the previous experience in the legislative sphere are factors influencing the legislative success of a parliamentarian. Also, legislative efficiency rises with an increase of a deputy's term in office. The author concludes that the institutional characteristics that make some deputies more effective legislators than others are crucial for the development of a more profound understanding of political representation and public policy-making.