Five children, three girls and two boys, were treated for precocious puberty secondary to hypothalamic hamartoma by resection of the hamartoma. The patients' ages at onset of pubertal development ranged from 6 to 19 months. The hamartomas ranged in size from 6 to 10 mm; four were pedunculated, one was sessile, and all were located below the tuber cinereum. The hamartomas were excised via a right subtemporal approach, with transection at the inferior surface of the hypothalamus; two were adherent posteriorly to the basilar artery and brain stem, and the adhesions were divided. Postoperatively, three children exhibited a transient oculomotor paresis and one other child required eye-muscle surgery. The symptoms and signs of precocious puberty completely regressed postoperatively in all patients. Preoperative hormone assays of testosterone, luteinizing hormone, and follicle-stimulating hormone were within the pubertal range in all five children; postoperative assays fell to prepubertal levels. The children have been followed for 0.5 to 10.5 years (mean 5.0 years) postoperatively, without evidence of recurrence of precocious puberty. One child has begun spontaneous puberty at a normal age. It is concluded that complete resection of hypothalamic hamartomas causing precocious puberty is curative.