The purpose of the present study was to determine how the fatigue exercise affects the balance performance of individuals with mental disability, to evaluate the changes in their balance performance and electromyogram (EMG) during exercise, and to compare their values with those of healthy individuals. Educable mentally disabled individuals (n=14) and healthy sedentary individuals (n=14) were included in the study. Group 1: Included healthy balance and EMG control group, Group 2: Included the healthy individuals who were directed to perform fatigue exercise and from which EMG results were taken by means of balance scores, Group 3: Included the mild mentally disabled balance and EMG control group, and Group 4: Included the mild mentally disabled group who were directed to do fatigue exercises and from which balance and EMG results were taken. The subjects did the fatigue exercise only once for a period of 3 minutes at the submaximal intensity on the bicycle ergometer. While no differences were found within the pairs of groups, differences were found between the groups of healthy individuals and groups of mentally disabled individuals in terms of the balance parameter. On the other hand, no significant difference was found in the EMG changes in the Vastus Lateralis and Rectus Femoris muscles. When the EMG data and the heart rates recorded during the 3-minute exercise carried out with bicycle ergometer were examined, while no significant difference was found between the groups, significant differences were found between the distance, power and work values of these groups. Consequently, it was determined that there was a difference between the mentally disabled individuals and the healthy individuals of the same age group in terms of balance parameters; that physical exercise noticeably decreased the balance performance; and that mentally disabled individuals could get exhausted more quickly than their peers.