The article is devoted to the issue of reception in the family legislation of the first decade of Soviet power of certain foreign legal institutions. In particular, the Family Code of the RSFSR of 1918 borrowed the procedure of establishing paternity from the Norwegian law of 1915, and the Family Code of the RSFSR of 1926 borrowed the institution of “common law marriage” widely used since the XIX century in the USA. The question of creative revision of borrowed institutions in the Soviet legislation is considered. The problem of relevance of such historical-legal research in view of modern legislative initiatives is raised.