Aim: The study was undertaken to establish mammaglobin as a marker to differentiate between benign and malignant breast lesions. Materials and methods: The present study was undertaken at Osmania general hospital, Hyderabad from January 2012 to July 2013. A total of 60 samples of various breast lesions were studied. Immunohistochemistry was performed by using mammaglobin antibody. Results: Mammaglobin immunoexpression was seen in 75% cases of breast carcinoma. The invasive ductal carcinoma-NOS type showed stronger and diffuse staining pattern than other variants of breast carcinoma. Interestingly high mammaglobin expression observed in low grade tumours compared to high grade. Conclusion: Mammaglobin is over expressed in malignant breast lesions compared to non-neoplastic lesions of breast (P<0.05). The expression is high in low grade tumours compared to high grade tumours.