Background/objective: Breast cancer is a major concern worldwide and causes one of the highest numbers of causalities. The general approach for the evaluation of breast cancer has become formalized as triple assessment: clinical examination, imaging (usually mammography, ultrasonography, or both), and needle biopsy. Prostatespecific antigen (PSA) has been reported to be a potential biomarker of breast cancer. The objective of the present study was to determine the diagnostic accuracy of Prostate specific antigen for the detection of malignancy in breast tumors keeping histopathology as the gold standard. Subjects and methods: This cross-sectional study was conducted at the Department of Pathology, Quaid-e-Azam Medical College, Bahawalpur Victoria Hospital Bahawalpur from April 15, 2013, to October 14, 2013. All the patients with breast lump attending Surgery Outpatient Department were included in the study. Blood samples were collected in 5 ml sterile syringes on the same day before the FNAC was done. The total prostate-specific antigen of patients was assessed by commercially available ELISA kits and values >5 ng/L were labeled as positive. Results: Total of 230 patients were included in the study. The mean age of patients was 42 years with a standard deviation of 11.681 years. About 182 patients had breast cancer on histopathology while 160 patients were positive for PSA. PSA was found to be 78.2% precise in detection, the sensitivity of 80.2%, specificity of 70.8%, and positive predictive value of 91.2% and negative predictive value of 48.5%. Conclusion: Prostate specific antigen (PSA) has significant diagnostic accuracy in breast cancer and can be used as a diagnostic and prognostic marker of breast cancer in women.