Currently, parental leave is the most important tool of family policy in many countries of the world. According to researchers, parental leave can contribute to the development of gender equality, ensure a stable level of employment of workers with children and even increase the birth rate in the country. Despite the importance of the issue of parental leave, it remains practically unexplored in the Russian scientific literature. The article develops the design of a comprehensive study of the Russian parental leave system and the possibilities of its transformation. The purpose of the study is to develop methodological foundations for the organization of a sociological study of the possibilities of transformation of the Russian system of parental leave. The methodology is based on the study of the parental leave system as an instrument of family, social and demographic policy. The results of the study. The authors propose to study the parental leave system at two levels - at the level of state regulation and family organization. It is proposed to study the state regulation of parental leave by means of a regulatory analysis, and the family organization by means of a survey of parents on parental leave. For each level, a system of empirical indicators has been developed. Research prospects. It is planned to conduct empirical studies using the proposed methodology. This will expand the range of determinants of fertility, define in more detail the barriers that arise when combining work and parenthood and assess parents' satisfaction with the existing parental leave system.