Abstract: Objective : To explore the clinicopathologic features of secretory carcinoma of the breast (SCB). Methods :Tissues from 4 cases of SCB were analyzed by light microscopy, histochemistry, immunohistochemistry andelectron microscopy. The clinical data were also reviewed. Special staining using periodic acid-Schiff with dias-tase pretreatment and immunohistochemical staining of ER, PR, HER-2, p53, MIB-1, S-100, p63, CK8/18 andEMA by En Vision method were performed. Results : Solid, cribriform, tubular, and papillary architecture wereobserved. The tumors had cystic spaces filled with abundant pale pink secretory material, positive for dias-tase-resistant periodic acid-Schiff (PAS-DR) staining. Tumor cells were small with bland nuclei and abundantpale, eosinophilic cytoplasm, rare mitotic activity and necrosis. Immunohistochemically, tumor cells were posi-tive for CK8/18 and EMA, negative for S-100 and p63, and variably partially positive for p53, ER, PR, HER-2and MIB-1. Under electron microscopy, the tumor cells presented with numerous membrane-bound secretoryvacuoles in the cytoplasm lined with microvilli. Conclusion : SCB is a rare neoplasm, with low malignancy. Itspathology, clinical features, treatment, and immunohistochemical and genetic features are different from thoseof other types of breast ductal carcinoma.