We retrospectively analysed the clinical and CT findings of 24 cases with tuberous sclerosis with special emphasis upon the atypical presentation. The cases with classic clinical triad were accounted for in 21%, while 33% present6ed with atypical clinical features. The most common and characteristic CT finding is that of the subependymal calcified nodules of the lateral ventricle, which was seen in 85% of our cases. Cortical tuber and white matter lesions were demonstrated in 65% and 55%, respectively. Three cases showed cortical tuber and white matter lesion without subependymal tuber. The cortical tuber usually exhibited low density or calcified lesion, but showed high density in 2 cases. Other findings of tuberous sclerosis included intraventricular tumor, ventriculomegaly, and cortical atrophy. One case clearly demonstrated parenchymal tuber on MR imaging. In conclusion, diagnosis of tuberous sclerosis is usually made on the clinical bases initially However, CT and MR are lso diagnostic even in unusual clinical presentation such as unexplained retardation or epilepsy or when the classic clinical triad is incomplete. If only cortical tuber or white matter lesion is present, it is difficult to diagnose tuberous sclerosis and to differentiate from other cortical mass lesion. Therefor, careful evaluation is required with familarity with the atypical appearance of the disease.