Abstract The following case describes two spontaneous chronic subdural hematomas in one patient. The hematomas occurred on opposite sides. The patient had good blood pressure control and a normal creatinine. He was not receiving any anticoagulants or antiplatelet drugs. An angiogram was done after the second subdural collection was drained. There was no evidence of a vascular lesion. The possibility remains that patients with adult polycystic disease may be predisposed to develop spontaneous subdural hematomas in light of another report of five other cases. [copy ] 2001 by the National Kidney Foundation, Inc.