Cause and effect of emergence and development of non-formal adolescent groups are analysed. This process depends on objective and subjective factors. Psychological needs of forming person such as self-consolidation, self-realization are at variance with the formalism in educational institution's activity. As a result there are no necessary conditions for individual self-constitution and active social development of adolescents. The peculiarities of non-formal youth formations (their complexity, heterogeneity, tendencies of development) are examined. The ways of application of spontaneously found forms of organizations and socially useful activity are discussed. The psychological conditions and possibilities of restructuring of educational work are shown.