The purpose of the research was to study the influence of self-estimation of athletic performance on the success of the athletes' activity. The essence of the research The research was conducted using a number of psycho-diagnostic methods which are the following: G.U. Eysenk's personal questionnaire, N.B. Stambulova's self-estimation of willed features, G.V. Lozova 's technique of diagnostics of motivation for sport activity, scale of athletic performance self-estimation. The object of the research were athletes of various qualification in the age of 17-26, specialized in various kinds of sport, with the training experience of 1-17 years. The results of the research The carried out analysis has shown the presence of parameters marked by the athletes of one kind of sport and not marked by the athletes of the other one. Athletes with high, adequate and stable self-estimation are more successful in sport. The self-estimation of athletic performance of the athletes engaged in various kinds of sport incr