Children suffering from chronic diseases have already met with the fears they bring from their early age. Type I diabetes mellitus or diabetes is the most common form of diabetes that occurs in children of early and pre-school age. It appears because of the inability of the pancreas to produce insulin. Insulin addiction is absolute and treatment with diet and diet alone is not sufficient. Treatment of diabetes is complex, especially for the child, the daily insulin dose should not be skipped. The same as insulin and nutrition, one of the most important segments of diabetes treatment and Regulation is physical activity. Physical activity affects the complete child's body and gives positive effects in the positive physical and psychological sense. Five basic principles in the treatment of diabetes are: education, proper insulin therapy, proper nutrition, physical activity and self-control of GUK (blood glucose). Physical activity is one of these items that significantly affects glucose Regulation. A person with diabetes needs to assess the type of exercise that suits her best. Whether it is anaerobic, aerobic, interval or combined, it is important to conduct it regularly. In children, the type of exercise should be determined and adapted by parents and educators, listening to and watching the child, what exercises suit him, in which he feels comfortable, etc. Each activity has a different effect on glucose and disease control itself, but all species have a positive effect on the reduction of GUC, reduction of insulin intake, reduction of HbA1c (average 3-month glucose of GUC). Exercise is an integral part of diabetes treatment. The aim of this final work is to embrace and to detail how important physical activity is for the child, but also for the adult, and how much it affects the very developed disease of today, which is diabetes. The aim is also to show in the broader spectrum what is actually diabetes and how often it is, and how little is said and educated about it.