Although the incidence of epidemic encephalitis has decreased markedly nowadays, sporadic cases are still observed in Korea. In this study, CT findings of 17 patients with clinically and serologically proven epidemic encephalitis were analized. In principle, CT scans were done at the acute and subascute stage, within 20 days from onset. The results were follow: 1. Of all 17 patients with CT scan, normal scan were demonstrated in 3 cases and abnormal scans in 14 cases. 2. The abnormal CT findings were ; area of low density in 9 cases, brain edema in 7 cases, nodular and gyral contrast enhancement in 3 cases, central brain atrophy in 3 cases and hemorrhagic high density in 2 cases in order of frequency. 3. The CT findings, according to date of CT scan from onset, were; brain edema and area of low density within 10 days from onset, normal or central brain atrophy between 11 days and 20 days, area of hemorrhagic high density and contrast enhanced lesions at both stage. 4. The locational distributions were ; thalamus and cerebral white matter in 7 cases respectively, basal ganglia in 5 cases, cerebral cortex in 4 cases and septum pellucidum in 1 case in order of frequency. 5. The correlation between CT findings and prognosis; although the prognosis in cases with the CT findings of normal or only central brain atrophy is good, the prognosis in cases with other abnormal findings may be depending uon the severity of lesions in the brain. Perhaps with long- tern follow up, the CT scan may become more definite in prognosis.