We prospectively reviewed the clinical and neuroimaging features of 10 men and 7 women (aged 25-81) with recent superior cerebellar artery territory infarctions. Six patients had superior cerebellar artery infarctions restricted to one cerebellar hemisphere. The remaining patients had infarctions in more than one vascular territory (6 had bilateral superior cerebellar artery infarctions; 4 associated brainstem infarctions; 3 associated supratentorial infarctions and 5 infarctions in other cerebellar vascular territories). Presumptive etiologies were: 7 atherothrombotic, 6 cardioembolic (3 had atrial fibrillation, 1 with a left atrial thrombus; 2 had myocardial infarctions, 1 with a left ventricular thrombus; 1 had a paradoxical embolus with Ebstein''s anomaly and atrial septal defect), 2 vertebral artery dissection and 2 undetermined cause. Two patients died. Two patients suffered major morbidity; 1 developed hydrocephalus requiring ventricular shunting and the other had brainstem compression requiring emergent posterior fossa decompression. Superior cerebellar artery infarctions result from a number of causes, but are usually of presumptive atherothrombotic or cardioembolic origin. Although other reports suggest a benign course with superior cerebellar artery infarctions, they can be associated with serious morbidity or death.