Chorea is a hyperkinetic movement disorder characterized by a continuous flow of rapid, random, and involuntary bodily contractions, usually affecting the distal limbs. When these movements are more proximal or assume a larger amplitude with a flinging or kicking character, they’re referred to as ballism. These disorders can be associated with several causes, ranging from genetic and neurovascular to toxic, autoimmune, and metabolic. Non-ketotic hyperglycemic hemichorea-hemiballismus is a rare consequence of decompensated diabetes mellitus with a poorly understood pathogenesis but with characteristic MRI T1 and T2 hyperintense abnormalities in the contralateral basal ganglia.We present the case of a 74-year-old woman with a history of poorly controlled type 2 diabetes mellitus, dyslipidemia, and arterial hypertension who was admitted to the emergency room due to a two-day history of rapid non-stereotypical involuntary movements of the left side of her body. A neurological exam showed large amplitude and repetitive left-side body movements. Glycemia was 541 mg/dL with no ketosis. Her glycosylated hemoglobin was 14%. A brain CT excluded acute abnormalities. Brain MRI showed a discrete T1 hyperintense signal involving the right corpus striatum, compatible with non-ketotic hyperglycemic hemichorea-hemiballism syndrome. After metabolic optimization with insulin and haloperidol, the movements resolved. Early recognition and metabolic control are essential to the resolution of choreiform movements. Our aim is to raise awareness for hyperglycemic hemichorea-hemiballismus, in which decompensated diabetes is the early sign of diagnosis.