Choreoathetosis is complex, hyperkinetic, irregular, sudden and short-term movement disorder. Involuntary twisting movements are also seen together. Hereditary, immunologic, metabolic, neurovascular, infection diseases and drugs can cause this disease. It is more common in elderly people due to vascular diseases. It is more rare due to metabolic causes. A 73-year-old male patient presented with the complaint of was not being able to control the right arm for two days. There was choreoathetoid movements in his right arm, especially when he was walking. His blood glucose levels were high. Type 2 diabetes mellitus was diagnosed according to American Diabetes Association criteria. In brain magnetic resonance imaging, asymmetric hyperintensity was detected in the basal ganglia consistent with chronic ischemic lesions, more prominent on the left in T1 sequence. He was treated with subcutaneous insulin. Choreoathetoid movements declined after the third day and recovered on the 7th day. This is a consequence of the effects of basal ganglia, especially putamen. The reduction in the amount of GABA and dysfunction of GABAergic neurons are responsible from pathophysiology. Therefore, it is important to detect blood glucose and HbA1c levels in acute developing choreoathetosis.