This paper presents the results of the study which examined the effects of carefully designed physical exercise programs on the development of physical fitness in children with ID. The study sample consisted of 42 children with ID and 45 typically developing children. All the participants were assessed using Eurofit Test Battery. The results were analyzed in terms of participation in the exercise program and level of intellectual functioning. While ID children scored significantly lower on fitness tests when compared with typically developing children, the study revealed an association between degree of ID and physical fitness.