Three patients had recurrent focal motor seizures as the first manifestation of nonketotic hyperglycemia (NKHG) of diabetes mellitus. The seizures were characterized by stereotypical tonic changes in body posture and arrest of speech that have been associated with supplementary motor area seizures. Recognition of the link between this unusual form of focal epilepsy and NKHG would help in the early diagnosis and treatment of the serious underlying metabolic disturbance.