Isolated unilateral oculomotor nerve paresis is a rare presentation of midbrain cerebrovascular accident. This report describes a case of isolated unilateral oculomotor nerve paresis resulting from a tiny lacunar infarct in the midbrain. Given the patient’s poorly controlled type 2 diabetes, ischemic oculomotor nerve palsy was most likely etiology. However, diffusion-weighted magnetic resonance imaging (MRI) of the brain revealed a subacute lacunar infarction in left midbrain.