Common (joint)-play and common work of preschoolers are compared. Both activities share similar communicative-organizational basis which makes it possible to compare them in an experiment along some social-psychological dimensions. It has been noted that play is more accessible for the children: here their behavior is more interrelated, and functional duties are here distributed in a more optimal way. A conclusion is made about the necessity to improve the methods of supervision in relation to the common activity of pre-school children.