Brain tumors, hematological diseases and vascular malformations like fistulas or arteriovenous malformations are the most well known causes of non-traumatic subdural hematoma (SDH) (1). Although spontaneous subdural hematoma from ruptured intracranial aneurysm has been reported (2), SDH with non radiographic evidence of subarachnoid hemorrhage is very rare (3,4). Moreover, a patient with acute and bilateral spontaneous subdural hematoma secondary to ruptured left posterior communicating artery aneurysm has not been reported to date. The clinical findings and etiologic mechanisms are discussed.