Аннотация:This article describes the specifics of using computers and computer pro-grams in developmental work with children of preschool age. The concept of a computer game and the activity mediated by the computer is discussed. We present analysis of modern computer programs for preschool children, including shortcomings and risks of the usage of entertainment programs. Design stages of the computer program from the point of view of activity approach are introduced. Two types of developmental computer programs are appointed: closed and open type. Advantages of programs of open (creative) type are shown. The contents of a uniquely designed computer pro-gram of open (creative) type are described, with indication of the principles that methodology of the lessons is based upon. Finally, we present the results of a formative experiment, which showed that the developmental computer program and the suggested methodology of lessons promote development of certain components of systemic thinking, general integral indicator of systematic, as well as flexibility of thinking and imagination of senior preschool children.