Complications of bone marrow trephine are thought to be uncommon. Herein, we present a case of severe debilitating sciatic nerve palsy secondary to a gluteal artery pseudoaneurysm following bone marrow biopsy. The pseudoaneurysm was treated successfully by percutaneous embolization; however, the patient remains significantly impaired with persistent painless foot drop. (C) 2005 Elsevier Ltd. All rights reserved.