Anticoagulation therapy in 74 patients with gynecologic malignancy and venous thromboembolism was evaluated as to hemorrhagic complications, recurrent thrombosis, and completion of prescribed course. Clinically significant bleeding complications occurred in 25 patients and the course of anticoagulant therapy was not completed in 29 patients because of bleeding complications or death within 3 months. Venous thromboembolism recurred in 11% of patients. Risk factors associated with hemorrhagic complications and unsuccessful completion of anticoagulation therapy include advanced age, advanced stage of malignancy, incomplete surgical resection of tumor, and systemic chemotherapy. Complications of anticoagulant therapy were found to be excessive when compared to those in reports dealing with noncancer patients and may exceed the benefits of therapy in certain patients. Alternative methods of management for this group of high-risk patients are discussed.