13 cases of atypical meningioma were analysed, which were proven surgically in S.N.U.H. for 3 years since March, 1979. C.T. findings of atypical meningioma were central low density in 8 cases, large cyst in 4 cases, calcified mass in 1 cases and non-specific scalp mass in 1 case. All the CT findings of atypical meningioma were pathologically proven as follows. Central low density was tissue necrosis in 5 cases, multiple cysts in 2 cases and hemorrhage in a case. Large cyst was arachnoid cyst in all 4 cases. Calcified mass was massive calcium deposition on tumor. Non-specific scalp mass on temporal area was meningioma involving soft tissue, bone and dura.