Although breast tuberculosis still remains rare, but in endemic countries should be in differential diagnosis of breast cancer and abscess. Imaging modalities cannot distinguish between cancer and tuberculosis. Acid fast bacilli stain; culture and PCR are helpful diagnostic methods but unfortunately are not very sensitive. Negative results do not rule out this diagnosis, so it seems definite diagnosis can be made by open biopsy and histologic evidence (granuloma tissues). In this case, a 33 years old woman was referred to the Infectious Ward in Imam Reza Hospital, Medical University of Kermanshah, western Iran in 2011; complaining of one lump in her left breast which did not response to usual therapy (painkillers and antibiotics). Fine needle aspiration for histologic and cytologic evaluations were negative but open biopsy showed granulomatous tissues, anti-tuberculosis chemotherapy was begun and response was significant then PCR was reported positive. We think in endemic area, empirical treatment can be started based on histological evidence and proper clinical manifestation.