Background:Gynecomastia during adolescence is common though etiology is not clear. We studied the clinical and hormonal profile of adolescent patients with gynecomastia.Methodology:Patients who had onset of breast development between age 10 and 20 years were included in this study. Their clinical profile, biochemical, and hormonal parameters were studied.Results:Of 94 patients with gynecomastia, 4 had hypogonadotropic hypogonadism, 4 had hypergonadotropic hypogonadism, and 1 had fibroadenosis, but in majority (90.4%), no apparent cause for breast enlargement was evident. In the idiopathic group, majority were obese (63%). Fourteen (16%) patients had impaired fasting glucose or impaired glucose tolerance. Another twenty patients had subtle abnormalities (high 1 h glucose or glucose peak at 2 h). Twenty-nine percent of lean and 38% of obese patients had mild abnormalities in glucose profile. Sixty percent of patients had family background of diabetes. Obese patients had lower testosterone as compared to lean patients; however, estradiol, luteinizing hormone, and follicle-stimulating hormone levels were similar in the two groups.Conclusion:Gynecomastia during adolescence is associated with obesity, dysglycemia, and family background of diabetes mellitus.