Twenty patients with malignant bone tumors of the hip region were treated surgically by resection and reconstruction with an endoprosthesis. Histologic types included five primary bone tumors and 15 metastatic lesions. At review four primary bone tumor patients are still alive without evidence of disease. The length of the observation period varied from 26 to 104 months. Eleven patients with metastatic bone disease died. The average postsurgical survival time was 23 months. All patients were able to walk with or without a cane. Failure of an endoprosthesis occurred in one case. According to the Enneking Evaluation System 11 patients had a good and 9 a fair result.