Male breast cancer (MBC) is a rare disease compared to female breast cancer (FBC). It accounts less than 1% of all breast cancer and less than 1% of all men cancer. Male patients with breast cancer are treated according to treatment guidelines of FBC specifically the guidelines of post-menopausal FBC based on the high expression of estrogen receptor (ER) which found in the tumor of MBC and post-menopausal FBC patients and low estrogen expression in their bodies. In this retrospective study, we aimed to compare MBC to FBC to understand the biological behavior of MBC and the outcome of this disease. Patients and methods Patients diagnosed between 2005-2012 with breast cancer were included in this study, their number was 477 cases. Patients were classified according to sex into male (number=17) and female (number=460) breast cancer. We compared the incidence, tumor characters, adjuvant treatment, the 5-years disease free survival (DFS), and Overall survival (OS) of MBC to FBC. Results MBC cases were 3.6% compared to 96.4% FBC cases which were highly significant. As regarding to the stage of the tumor at diagnosis, no differences were seen between MBC and FBC, 82.4%stage I & II for MBC versus 77.4% for FBC and 17.3% stage III & IV for MBC versus 22.6% for FBC. No significant difference between MBC and FBC as regarding the type of pathology, ductal carcinoma in situ (DCIS) was found in 5.9% versus 1.3%, invasive ductal carcinoma (IDC) was found in 94.1% versus 96.7%, and invasive lobular carcinoma was found in 2% of FBC only. Most of patients expressed positive estrogen receptor (ER), 88.2% for MBC versus 75% in FBC (P0.04) while 70.6% of MBC were progesterone receptor (PR) positive versus 71.1% in FBC. As regarding to HER2/neu status 23.5% was positive in MBC versus 66.7% positive in FBC (P0.04). According to adjuvant treatment there were significant differences between MBC and FBC. There was no difference between MBC and FBC as regarding DFS. The median DFS was 3.9 years for FBC versus 3.4 years for MBC. In term of OS, the MBC had poor OS compared to FBC. Conclusion MBC outcome was inferior compared to FBC that may be due to the differences in the biological behavior of MBC. More studies are needed for further understand the differences between MBC and FBC. [Rehab F Mohamed. Comparison between Male Breast Cancer and Female Breast Cancer, Retrospective Study. Cancer Biology 2017;7(3):21-25]. ISSN: 2150-1041 (print); ISSN: 2150-105X (online).