Movement disorders such as chorea and ballism rarely occur in diabetes mellitus. We report the case of 26-year-old man with a 13-year-history of type 1 diabetes mellitus. He presented with a right side hemichorea. Brain CT-scan and MRI showed an infarction of the head of the caudate nucleus and the anterior part of the putamen. Presence of microangiopathy affecting retina, kidneys and peripheral nerves suggest a similar involvement of the lenticulo-striatal arteries. Hemichorea and hemiballism usually occur in older patients presenting type 2 diabetes mellitus. Non-ketotic hyperglycaemia is the common cause in such situation. Striatal infarct, as seen in our patient, is rarely reported.