The number of adult male patients with acute gynecomastia is progressively increasing. In the examined sample of patients, the main causes of gynecomastia were patients taking anabolic steroids, liver dysfunction and weight gain with the formation of changes in sex hormone levels. Patients taking anabolic steroids were characterized by a drug--induced increase in testosterone and estradiol levels, which was accompanied by suppression of pituitary gonadotropic function. Estradiol elevation was also characteristic of patients with hepatogenic form of gynecomastia and men with excess body weight with formation of changes in sex hormone levels.