Objective To study the clinical manifestations and MRI characteristics of hypothalamic hamartoma. Methods The clinical manifestations and MRI findings of 18 chlidren(included 10 boys and 8 girls,ranging in age of onset from 6 months to 12 years) with hypothalamic hamartomas proved by surgery and pathology were retrospectively reviewed. 14 patients were examined with precontrast and postcontrast MR imaging,only 4 were scanned without contrast study. Results The main clinical features of the hypothalamic hamartomas were due to gelastic epilepsy and precocious puberty. Gelastic epilepsy was found as initial clinical symptom in 9 cases, precocious puberty in 5 cases, limbs spasm in 2 cases,motor developmental retardation in 2 cases. MRI showed abnormal single nodules located in the suprasella and hypothalamic regions with round or elliptical shape. All mass had sessile attached to the part of tuber cinereum and mammillary body. The dimeters of the mass ＜15mm and ＞15mm in 14 and 4 cases. On MRI, the mass was isointense or slightly hypointense on T1WI and isointense or slightly hyperintense or hyperintense on T2WI relative to gray matter,16 of 18 cases the singnal was very homogeneous, two of them combined with necrosis. And no enhancement was observed. Conclusion There were characteristic findings in the clinical manifestations and MRI to evaluate hypothalamic hamartomas. Hypothalamic hamartomas should be considered firstly when patient have the symptom of gelastic epilepsy and precocious puberty,as well as non-enhanced round shape nodules located in the suprasella and hypothalamic regions