Chorea-ballismus which is a rare complication of nonketotic hyperglycemia may be the first symptom of type 2 diabetes mellitus. In this paper, we present two patients, who had involuntary movements and were diagnosed as having ballismus-chorea associated with nonketotic hyperglycemia. While one of the patients was not diagnosed with diabetes mellitus, the other one did not administer insulin therapy for a long time which was prescribed. The patients were investigated by cranial imaging and biochemical tests. The symptoms improved in one of them within hours, however, it took days to improve for the other one. This clinical situation, which is thought to be caused by hyperglycemia, cerebral ischemia and failure of gamma-aminobutyric acid (GABA) and which probably improves with regulation of blood glucose levels, should be kept in mind by emergency physicians, because it can be the first presentation of type 2 diabetes mellitus.