In the primary mammary malignant tumors, including in situ carcinoma, it is recommended the carrying out of immunohistochemical diagnosis for the estrogen (ER) and the progesterone receptors (PR). We have studied the ER and the PR expression in malignant tumors, trying to identify the corresponding phenotypes according to the presence of these tumors. We have carried out a study on a total number of 80 carcinomas, divided into two groups: the first one constituted of 54 cases of carcinomas on which we had clinical data, and another group, constituted of 26 cases of mammary carcinoma, where no clinical data was available. We have observed that the values and the distribution of the ER and PR taken from the biopsies made in the patients with mammary carcinoma are influenced by the age and menopausal status. The combination of the ER/PR results lead to the definition of many tumoral phenotypes.