In this study, the relationship of prostate specific membrane antigen (PSMA), a type-2 transmembrane glycoprotein, with the Her-2 Receptor and prognosis of the disease in cases with Paget's Disease of the Breast was investigated. The data of 14 patients diagnosed and treated with Paget's disease of the breast between July 2013 and March 2020 in the General Surgery Clinic were evaluated retrospectively. After the pathological diagnosis was made, all patients underwent modified radical mastectomy. Paget's disease was found together with invasive ductal carcinoma in one patient, and Paget's disease was found together with ductal carcinoma in situ in 7 patients (50%). Staining in malignant tissue with PSMA was detected in only two patients. The normal dermis venules of other patients were stained with PSMA. In the subsequent follow-ups, lung and bone metastases were detected. The other patient stained with PSMA showed weak PSMA expression in malignant epidermal cells in the epidermis (The patient's tumor invasion grade was T2, there was no axillary lymph node metastasis, ki-67 expression was 10%, estrogen, progesterone and HER2 receptor were positive. Although studies showing the relationship between PSMA and breast malignancies are limited and there is no lite rature information; In our study, two patients with staining with PSMA had high grade and distant metastases with ki-67. Larger studies are needed to establish a link between PSMA and Paget's disease of the breast.