This article examines one of the central problems of positive psychology - the identification of biological determinants of psychological well-being of an individual. The importance of researching the psychological well-being of an individual is determined by the social demand for identifying the content characteristic of this phenomenon, its links with other factors, both socio-psychological and biological. To date, science is equipped with data on psychological well-being, such as its structure and knowledge of the factors affecting this phenomenon. However, the study of psychobiological determinants of psychological well-being of an individual is outside the sphere of scientific analysis. The method of theoretical analysis of scientific literature and the methods of statistical data processing, in particular the Pearson correlation ratio and the Mann-Whitney U-test to solve the problems posed, were used. The study included the use of a set of standardized psychodiagnostic methods of questionnaire type. In the course of empirical study, we established that the psychological well-being of an individual had a direct relationship (p≤0.01) with social ergity, and object plasticity (p≤0.01); with a social rate (p≤0.01). A statistical comparison according to Mann-Whitney U-test showed that the formal dynamic properties of individuality were more developed in respondents with a high level of psychological well-being. The results obtained in the course of study are of great theoretical and practical importance. So, we have the opportunity to develop the psychological well-being of an individual by influencing the psychological and social component of the psychobiological structure of individuality.