<p><strong>The relevance.</strong> The play in Russia is most often considered in connection with the mental and volitional development of a child. At the same time, according to the classics of psychology, specific affect lies at the center of the child play. It is characterized by the presence of positive emotions related to the structure of the play. It is important that a positive emotional state is crucial for the psychological well-being of a child. At the same time, there remains a significant shortage of research in Russia devoted to the study of the influence of play on the psychological well-being of a child. <strong>Goals.</strong> Analyze the importance of the play for the psychological well-being of children and adults. <strong>Results.</strong> The play has a special device &mdash; ambiguity &mdash; which leads to the splitting of affect: part of it is related to the content, and the other part is related to the form of the play. The emotions associated with the structure of the play are always positive. Such a device of the play explains its positive effect on the emotional state of the player. In the process of a child's development, play contributes to the appearance of a specific personality trait &mdash; playfulness. Playfulness is measured using special scales, also at any age period. <strong>Conclusions. </strong>Play is extremely important for maintaining the psychological well-being of the child. Due to the fact that the culture of the play is transmitted from adults to children, it is important that adults know how and love to play. The tendency to play can be considered as a personal trait of children and adults. Playful adults have higher rates of psychological well-being, but also they create the necessary conditions to maintain the psychological well-being of the child.</p>