BACKGROUND We review the surgical treatment of hypothalamic hamartoma causing precocious puberty. METHODS Six children (three girls and three boys) with precocious puberty secondary to hypothalamic hamartoma were recruited for our study. The mean age of the patients was 30 months old (range 13 months to 5 years), and the mean age of the onset of puberty was 7.3 months. All patients were treated by microsurgery. RESULTS All patients had higher then normal stature, body weight, bone growth, and serum levels of sexual hormones. The boys presented with mature external genitalia, pubic hair, frequent erection, and acne, while the girls presented with growth of breasts and menarche. Magnetic resonance image (MRI) revealed an isointense mass below the tuber cinereum extending into the supersellar and interpeduncular cistern, ranging from 4 to 12 mm in diameter, consistent with pedunculate hamartoma. The hamartoma was removed completely via a right pterional approach. The symptoms and signs of precocious puberty resolved completely, and sexual hormone levels decreased to the pre-pubertal range in all six patients without any postoperative complications. CONCLUSION We report a series of six children with hypothalamic hamartoma-induced precocious puberty who underwent microsurgical treatment. All of them recovered completely to their age-appropriate state. Microsurgery is a good choice of treatment for pedunculate hypothalamic hamartoma. (C) 2002 by Elsevier Science Inc.