A retrospective study carried out at Kasr El Aini Centre of Clinical Oncology and Nuclear Medicine (NEMROCK) Faculty of Medicine, Cairo University during the period January 1995 to December 2000. A total of 211 patients with metastatic breast cancer were studied to identify various prognostic factors and the effect of primary site of metastases on clinical course, prognosis and treatment outcome. Overall survival and time to develop metastases was affected by primary site of metastases .