BACKGROUND Patients with cancer who undergo surgery about the hip are at increased risk for the development of deep vein thrombosis. We implemented a program of chemical and mechanical prophylaxis to prevent this problem. This study was performed to assess the effectiveness of that program. METHODS Eighty-seven consecutive patients with an active malignant tumor who underwent hip replacement surgery at our institution over a two-year period were included in the study. All patients were treated with intermittent pneumatic compression devices. Seventy-eight patients received anticoagulants, and nine did not. Postoperative surveillance for proximal deep vein thrombosis was routinely performed on all patients with duplex Doppler ultrasonography. RESULTS Four patients had proximal deep vein thrombosis, and one patient, who did not receive anticoagulation, had a nonfatal pulmonary embolism. The use of prophylactic low-molecular-weight heparin (dalteparin) was associated with a 4% rate of proximal deep vein thrombosis (three of seventy-eight patients). Proximal deep vein thrombosis developed in three of eight patients with pelvic disease, one of nineteen patients with femoral disease, and zero of sixty patients with hip disease (p < 0.00001). The prevalence of proximal deep vein thrombosis was significantly higher (p < 0.02) following replacements in patients with sarcoma (three of twenty-one) than it was after replacements in patients with carcinoma (zero of fifty-seven) or hematologic malignant disease (one of nine). On multivariate analysis, only the location of the disease (the pelvis, femur, or hip) was found to be independently significant for an association with deep vein thrombosis. A wound complication developed in four of twenty-one patients with sarcoma and no patient with carcinoma or hematologic malignant disease (p < 0.001). The pathologic type was the only factor studied that was independently significant for an association with wound complications on multivariate analysis. CONCLUSIONS The rate of proximal deep vein thrombosis in patients who had undergone hip replacement for oncologic indications was low when the use of an intermittent pneumatic compression device was supplemented with prophylaxis with low-molecular-weight heparin.