The acute toxicity of the combined vaccine (KGCC-95VI) for the prophylaxis against Japanese encephalitis and Hantaan virus infection. recently developed by Korea Green Cross Corporation, was investigated. KGCC-95VI was administered to the Balb /c mice in two routes, orally and subcutaneously, and into the New Zealand White rabbits subcutaneously. $LD_{50}$ was not accessible as there were no deaths in the group treated even at a dose 800 times the expected clinical dose in both animal species. Between the treated and control groups there were no statistically significant differences in body weight changes and clinical signs during the 14-day observation period, and no pathological gross findings. Accordingly KGCC-95VI is considered not to have the acute toxicity in mice and rabbits.