Background: Breast cancer has shown an increased prevalence worldwide, both in industrialized and developing countries. Unfortunately, most cancers do not produce any symptoms until the tumors are either too large to be removed surgically or metastasis has taken place. Therefore, there is need for simple biochemical investigations, which can be easily assayed, less expensive and can predict stages and prognosis. This study was undertaken to know the usefulness of estimation of serum Alkaline Phosphatase (ALP) in assessing the prognosis and staging of breast cancer in smaller laboratories where sophisticated technology is not available. Materials & Methods: A total number of 95 subjects participated in the present study which included 60 breast cancer cases and 35 controls. Serum Alkaline Phosphatase levels were estimated in preoperative & postoperative breast cancer subjects of different stages and control. ALP Levels were compared between control and breast cancer. Also comparison was done between different stages and further, ALP levels compared pre and post operatively. Results: Rise in the ALP was found in breast cancer when compared to controls. ALP levels increased significantly with the stage of cancer. Postoperatively, there was significant decrease in ALP levels in each stage. Conclusion: Though less sensitive than imaging procedures, measurement of serum ALP is cost effective and may be useful in smaller laboratories for staging, to know the prognosis and monitor the treatment. Serial analysis using plasma Alkaline phosphatase isoenzymes combined with other parameters like Gamma glutamyl transferase (GGT) for the detection of metastasis would seem to be justified.