A 64-year-old female receiving clopidogrel and aspirin antiaggregation therapy after percutaneous coronary intervention for non-STEMI myocardial infarction developed nontraumatic bilateral subdural hematoma with dizziness, vertigo and headache. Craniotomy had to be postponed because of reduced ADP platelet aggregability. Four days after clopidogrel withdrawal and transfusion of 12 platelet concentrate units, ADP aggregation transiently normalized and bilateral trepanation with hematoma evacuation was performed. The procedure was followed by excellent neurologic and clinical recovery; however, decreased platelet aggregability was recorded by postoperative day 12 despite strict clopidogrel and other platelet inhibitor withdrawal. Suspicion of Glanzmann thrombastenia was excluded by flow cytometry. Two weeks after neurosurgery, the right femoral vein thrombosis was detected by color doppler ultrasonography and therapy with fractionated heparin was initiated, followed by warfarin. The risk and incidence of hemorrhagic complications of antiaggregation and anticoagulation therapy are discussed. Caution is warranted on prescribing this potentially harmful therapy to older patients, generally burdened with other chronic comorbidities.