Even though the nonketotic hyperglycemia is a metabolic disorder, it complicates hemichorea-hemiballism rarely. Moreover, generalized chorea-ballism associated with nonketotic hyperglycemia in diabetes mellitus is very rare, so it has not been reported in Korean literature. Although the precise pathophysiologic mechanisms of these disorders are still poorly understood, deficiency of gamma aminobutyric acid (GABA) in nonketotic hyperglycemia or reduced GABAnergic inhibition by striatal lesion may increase inhibitory output to subthalamic nucleus. These result loss of pallidal inhibition and produce contralateral hemichorea-hemiballism. The striatal lesions, such as transient ischemia with reactive astrocytosis or small amount of petechial hemorrhage, are related with changes of magnetic resonance image (MRI) findings presumably. We report a diabetic old woman who developed generalized chorea-ballismus as a very rare complication of nonketotic hyperglycemia. Her brain MRI showed high signal intensity in left lentiform nucleus and right pallidum on T1 weighted images and low signal intensity in bilateral putamen on T2 weighted images with highly enhanced corresponding lesions on T1 weighted enhancement images.