Breast pathology, during adolescence, shows a typology like that in adults but with a completely different incidence. We observed 472 patients aged between 12 and 19 years in Senology Center of II Clinic of Obstetrics and Gynecology from 1984 to 1992. The most frequent pathologies diagnosed were: fibroadenomas (in the variety simple, phylloides, giant), cysts (simple and apocrine cysts); lower incidence for congenital anomalies, mastitis, mammary secretion caused by ductal hyperplasia or intraductal papilloma, lipoma. No incidence of cancer was detected. Echography was the principal diagnostic method for those patients who showed, at the clinical examination, a lump or palpable abnormalities. Mammography in this period does not affect the diagnoses and can be potentially harmful due to the exposure at X rays on such a sensible tissue.