The paper presents results of a study of the effect of man's characterological properties on some indices of the dynamics of professional self determination level of professional intentions, coordination between the intentions and interests, progress in vocational studies. Regularities in the manifestation of the effect revealed in the study present obvious theoretical interest due to the acute deficiency of studies of the total picture of the interplay of different factors operative in man's professional self-determination. The study established also a correlation between some professional interests and characterological properties. The results obtained can be of use to educators engaged in development of vocational interests, dispositions, and intentions, as well as to guidance counselors.