Gynecomastia, defined as a palpable disk of breast tissue in males, is a relatively common condition. It is usually benign and self-resolving, especially in neonates and pubertal boys. An imbalance in the estrogen-to-androgen ratio is believed to be the culprit in the pathophysiology of gynecomastia. An increase in estrogen or a decrease in androgen is found in most pathologic entities associated with gynecomastia, such as hypogonadism, tumors, or enzymatic defects. A thorough history and physical examination is essential in distinguishing between benign and pathologic gynecomastia, as well as in directing further workup. Treatment of gynecomastia is usually for social and cosmetic reasons, and it is unnecessary in cases where it is mild or transient. However, in persistent or severe cases, treatment may be advisable. Androgens, antiestrogens, and P450 aromatase inhibitors have all been studied, with mixed results. Surgical treatment, while invasive and likely to leave scars in severe cases, is a definitive and more effective treatment option.