Hamartoma of the hypothalamic area is a well-recognized cause of central precocious puberty. We report a case of histologically proven hypothalamic hamartoma in a 8-year-old girl with precocious puberty. The CT showed an isodense, nonenhancing mass in suprasellar area, measuring 4.2X3.1cm. which, to our knowledge. seems to be the largest one of the published cases. On MR imaging, the signal intensity of the mass was homogeneous and isointense relative to gray matter on Tl-, and hyperintense on T2-weighted images. The clinical and radiologic findings of the published cases of hypothalamic hamartoma are reviewed.