CT abnormalites in the brain were retrospectively analyzed in 16 of 103 patients with acute leukemia confirmed by CSF cytology or combined surgery at Hanyang University Hospital, from August 1980 to August 1989. The results were as follows; 1. With FAB classification, the most frequent pathologic type was L1: 8 cases(50%) 2. The range of age distribution showed typical pattern that ALL occurred below the 15 years old, and AML, over 15 years old. 3. Abnormal CT findings were; Meningitis(2 cases), Mass(3), Thrombosis(1), Infarction(2), Edema(1), Hemorrhage(7),Hydrocephalus(2), Atrophy(2). 4. Most of itracranial hemorrhage were seen in M2 and M3 type.