Metastatic bone tumor is the most common bone tumor and 32.5% of all primary malignant tumors are eventually metastasize to bone. Metastatic bone tumor has been more frequently encountered disease in the orthopedic fields due to the greater longevity of life of the patients with primary visceral cancers by major advances in early detection, diagnosis, and surgical/radiotherapeutic/chemotherapeutic treatment of primary and metastatic lesions. Therefore, the epidemiologic data about the incidences and the patterns of bone metastasis is important. We reviewed 417 patients who were diagnosed and treated for metastatic bone tumor at Kosin University Medical Center from 1985 to 1993 to analyse the primary lesion, age and sex distributions, location of bone metastasis, patterns of metastasis according to the primary. The results were as follows : 1. The common origin of bone metastasis were lung(29.5%), stomach(15.3%), breast(11.3%), unknown(7.7%), cervix(5.3%), liver(4.8%) in order of frequency. 2. There were 251 men and 166 women and their mean age was 54.8 years and the peak age incidence was in 6th decades. Most cases(85.3%) were occured beyond 5th decades. 3. The preferred sites of metastatic deposits were spine(64.0%), pelvis(40.5%), rib(38.8%), femur(36.7%), skull(21.1%), humerus(13.9%), scapula(13.0%) in order of frequency. In the spine, thoracic(42.1%), lumbar(39.1%), cervical(13.2%), sacral(5.6%) vertebrae were involved in order of frequency. 4. Multiple bone metastases were more common(73.1%) than single metastasis(26.9%). 5. In the lung cancer, the peak age incidence was 6th decades, and the preferred sites of bone metastasis were spine, pelvis, femur. 6. In the stomach cancer, the peak age incidence was 6th decades, and the preferred sites of bone metastasis were spine, femur, pelvis. 7. In the breast cancer, the peak age incidence was 5th decades, and the preferred sites of bone metastasis were spine, rib, pelvis. 8. In the bone metastasis with unknown primary site, the peak age incidence was 7th decades, the preferred sites of bone metastasis were spine, femur, pelvis, and the common histologic types were adenocarcinoma and squamous cell carcinoma.