This study on the biological behavior of breast cancer in the Democratic Republic of Congo was done retrospectively on morphologically diagnosed patients in the cities of Lubumbashi and Kinshasa.89 patients were selected from two private pathological anatomy laboratories from January 2013 to December 2014. The diagnosis was confirmed by a laboratory in the Federal Republic of Germany thanks to the good care of the African Cancer Registry Network.The results show that breast cancer is diagnosed at an average age of 49.3 years and most often strikes women aged 51-61 years.Infiltrating ductal carcinoma is observed in 97.7% of cases. These observations are similar to those of several African authors in most of the parameters studied and could allow an extrapolation in aspects of these cancers in relation to the biology and the management of the patients.