In Special Olympics, athletes’ foot deformities, abnormal postural patterns and overweight and obesity were observed to be more common than in the general population. Therefore, the purpose of this study was to analyze the relationship between body composition and foot posture index. Additionally, the effect of gender and other factors on the body composition and foot posture index in athletes with intellectual disability (ID) were analyzed. Methods: 131 athletes with ID participated in this study: 36 table tennis players, 66 cross country skiers and 29 downhill skiers. Their body composition was assessed using the bioimpedance analysis InBody 230 (Biospace, Korea). The foot screening included the assessment of foot posture index, which evaluates the degree of pronated, supinated and neutral position of the foot, gait speed and the last part of the procedure consisted of a short questionnaire, providing the information about the type of housing, age, and the usage of orthotics. Results: A low correlation between body composition and some of the foot posture index criteria was observed. The mean foot posture index score in athletes with ID was observed to be slightly pronated, as also described in the general population, with no statistically significant difference between female and male athletes. The gender differences were observed only in body composition. Conclusions: The high body weight and body fat percentage observed in this study highlight the need for healthy lifestyle education in athletes with ID.