Early detection of neoplastic disease and metastatic spread is very important. Carcinoma of the breast is known to readily metastasize to the bone. The use of Tc-99m-phosphate as bone imaging agent has been shown to demonstrate early evidence of bone metastasis well before radiographic evidence is visualized and as thus become a very useful technique for estabilishing and monitoring the bony metastatic element of breast cancer. In this study, serial bone imaging studies were performed to monitor the management of 84 breast cancer patients before and after mastectomy and biopsy. We attempted to analyse bone scans of breast cancer and to correlate the scan findings with the clinical stage, status of lymphnodes, distant metastasis, bone pain, and laboratory datas. The following useful patterns were emerged: 1. Positive bone scan rate was definitely higher in clinical stage III and IV (42, 57%) than in stage I and II (4, 18%) in initial studies. However, no correlation between pos tive bone scan rate and clinical stage was found in follow up studies. 2. Positive bone scan rate was high in both groups with locally advanced tumor(T3 & T4) and distant metatasis. 3. No correlation between positive bone scan and status of lymphnode involvement was noted. 4. Positive bone scan rate was also very high in patients with bone pain and abnormal laboratory data.