The article discusses the problem of reduced play activity of a modern preschool. An overview of the research on the importance of the play as a factor in the development of the child in the preschool period of childhood is presented. The concept of «play dysontogenesis» is introduced, which means violated, not corresponding to psychological laws development of the play in preschool age due to a number of socio-cultural and educational factors. The reasons for the occurrence of play deprivation are revealed, which have a negative impact on the normal development of the child and the formation of the main neoplasms of preschool childhood. It has been shown that the simplification of the children’s play leads to mental and personal infantilism, a decrease in the ability to plan one’s own actions, a delay in the formation of significant mental functions and personality aspects, and a socio-normative disorientation of a growing person. Based on the data of individual authors and the materials of earlier studies, we suggest a high risk of the formation of various psychological dependencies and deviations, the emergence of play addiction and other socio-behavioral deviations as a result of a lack of play in preschool age. The results of familiarization with training curricula for preschool educational institutions are discussed, which indicate the complete absence in many programs of universities of theoretical disciplines, practical courses and workshops on psychology and pedagogy of children’s play, including applied aspects of teaching future educators how to organize and accompany preschool play. The conditions for the rehabilitation of the play as a unique social, psychological, cultural and age phenomenon, proposed by E.O. Smirnova as fundamental measures in modern preschool education, are outlined.