Gynecomastia is a pathological enlargement of male breasts due to hormonal imbalance and elevation of estrogens at the expense of testosterone. It is very important to diagnose this disease precociously because it can be the expression of different underlying pathologies. Besides genetic, chromosomal or chronic diseases, drugs often represent the principal cause of this hormonal disequilibrium. In the elderly population, antiandrogen therapy for prostate cancer frequently induces gynecomastia, thus negatively affecting the patients' compliance to treatment because of physical and psychological discomfort deriving from this condition; gynecomastia can in fact be associated with severe breast pain, and it can modify how patients see their own body. During the past decades and even today, many different surgical, radiotherapeutic or clinical approaches have been proposed to prevent or treat this hypertrophy. This article focuses on gynecomastia associated with antiandrogen-based hormonal treatment and shortly reviews the currently most often used therapeutic options for preventing and treating this pathology.