Cytosolic receptors for estrogens and progesterone are studied using an exchange method in various types of benign breast diseases: fibroadenomas, fibrocystic mastosis, phylloid tumors and gynecomastias. The results show clearly that, contrary to breast carcinomas, receptors are generally not present in benign tumors. These results are statistically significant for all the women studied. Studying the pathological aspects of the tumors, it can be noted that the presence of receptors, is correlated with proliferation forms with large epithelial components. Furthermore, these results show that receptors are not found in gynecomastia. In conclusion, the physician should follow up very carefully the patients with a benign tumor, when hormono-receptors are present.