The author designates the total of psychological information about work and worker as the sphere of the occupational psychology; science proper, as a branch of the scientific knowledge, constitutes one subdivision of it. Social necessities may require creation of a corresponding academic subject and of professional education. Occupational psychology as an academic discipline is assumed to be isomorphic to the professional culture which appears in the sphere of practical problems connected with the necessity to take into account the psychology of workers. Practicing psychologists are therefore assumed to represent the basic group of the professional community of occupational psychologists. The rest of the profession are to store and organize the traditions of the professional culture, to pass them to students, and to engage in the researches of urgent problems. The author names deed, as a specific unity of intention, performance and evaluation of performed, the unit of the psychological work. The article contains also an enumeration of main aspects of the occupational psychology as a field of science.