The paper presents theoretical and empirical grounds of the concept of psychological vitality. It is shown that scientific understanding of vitality phenomena tends to develop from structural, static, elementary conceptions towards notions of vitality as a specific integral property of human beings, essentially endowed with spiritual potentials. A description of a conceptual model of human psychological vitality is given. Results of empirical verification of the model are presented, including studies of everyday conceptions of a vital person, general structure and components of vitality, and ontological aspects of its expression.