The study examined the role of personality traits and value orientations of young people (both men and women) as factors contributing to the transition from an unregistered marriage to marital relations. The differences in the severity of personality traits and the importance of individual values among the partners living in unregistered and registered marriages were revealed. The sample of the study included two groups of respondents aged 18 to 35: partners in an unregistered marriage (cohabitation) - 144 persons (men and women 50% each) and partners in a registered marriage - 120 persons (men - 42.5%, women - 57.5%). The research methods and tools included: S.H. Schwartz’s Values Questionnaire (Personality Profile Section), 50-point form of L. Goldberg’s Five-Factor Personality Inventory and a scale for assessing the intention to marry and commitment to have and raise children. The results of both questionnaires were processed using the Multipsychometer hardware-software diagnostic complex, which converted the initial test scores into a 10-point equal-interval Sten scale. The presence and nature of the statistical influence was established using multiple linear regression analysis, statistical differences were identified using Student’s t -test and Mann - Whitney U -test. According to the results of the study, the personality trait “agreeableness” was the leading factor in the commitment to have and raise children as well as in the readiness to register a marriage with a partner. The significant differences in the severity of personality traits and the significance of individual values in the partners who were in a registered and unregistered marriage were identified statistically. It was found that the respondents in a registered marriage, compared with their counterparts in an unregistered marriage, had significantly more prominent personality traits such as “agreeableness” and “emotional stability” and, for them, the values “universalism”, “benevolence” and “self-direction” were more important. The obtained results can be used to scientifically substantiate practical recommendations for managers and specialists involved in the support and development of the family institution in modern Russian society, as well as in the practice of individual and family counseling.