Family structure is considered a particularly important predictor of social and political development; historical differences in family size and other family characteristics cast a long shadow over societal development. This paper explores the effect of differences in historical family size on political behavior based on within-country variations in this characteristic in Russia. Unlike most papers on historical legacies, we trace the effect of family size over a century of Russian history with a focus on the first competitive and free elections in Russia—to the Constituent Assembly—held in 1917 and on the presidential elections in post-Soviet Russia in 1996 and 2000. Mean family size is measured based on the census data for 1897. We find a robust and significant association between smaller family size and a voting preference for parties that are economically liberal, which holds despite differences in the political, economic, and social environment between the 1910s and 1990s