The incidence of breast cancer is increasing throughout the world as well as in India. Many risk factors and prognostic factors of breast cancer have been identified but the associations between mast cell infiltration and the clinical features of breast cancer remain unclear. The aim of the study was to estimate the mast cells number in malignant tumors and axillary lymph node and to find out any correlation between the number of mast cells and hormone receptor status. An institution based descriptive study was done in a tertiary care hospital. Total 44 specimens of post operative breast tissue with malignant breast lesion & dissected axillary lymph nodes were taken. Counting of mast cells was done in Toluidine blue stain. Immunohistochemical staining was done for ER, PR & HER2/neu using immunostaining kit. It was observed that when the tumor grade increases the number of must cell decreased per high power field. The mast cell count was significantly higher in cases of ER positive and PR positive breast cancers than that of the ER negative and PR negative respectively but there was no significant relation between mast cell count of HER2/neu. Mean mast cell count of triple negative cases was significantly low. This study indicated that the number of mast cells in breast cancer was inversely correlated with the grade of this tumor and higher mast cell count was related to good prognosis.