Bone scan measuring bone metastasis were analysed in fifty five patients diagnosed as malignant tumor, seven were primary bone tumor and forty eight were metastatic tumor, who treated in Kyung Hee Hospital from March 1981 to January 1982. The results were as follows: l. In 55 patients, positive bone scan were found in 76.4% of the patients and positive X-ray were found in 56.4%. 2. 7 patients with primary bone tumor showed all positive bone scan, 45 patients with metastatic tumor showed positive bone in 72.9%. 3. Among the patients with metastatic tumor who no clinical symptoms, positive bone scan were found in 59.3% and positive X-ray in 26%. 4. Most common metastatic site was femur in primary bone tumor and vertebra in metastatic tumor. 5. In 48 patients of metastatic tumor, positive bone scan within negative X-ray were found in 56%, negative bone scan within positve X-ray were found in 5%. 6 The lesions showed clod area on bone scan were considered of positive finding as compared with clinical symptom and X-ray finding.