A 78 year old woman developed repeated major pulmonary emboli following nasal resection for recurrent basal cell carcinoma. Lower extremity venography performed prior to planned insertion of an inferior vena caval filter unexpectedly revealed a large thrombus-containing aneurysm of the proximal popliteal vein. The aneurysm was excised and the vein repaired by lateral suture. Anticoagulation was continued for 3 months postoperatively. There were no further episodes of pulmonary embolism and popliteal vein patency was confirmed by duplex ultrasound 3 months postoperatively. The literature pertaining to these rare popliteal venous aneurysms is reviewed.