Influenza-associated encephalopathy is typically associated with a sudden onset of high fever, severe convulsions, rapidly progressive coma and death within 2 or 3 days. It has been actively researched in Japan as it caused a tremendous increase in the number of deaths from 1997 to 2002. But there has been reported only one case in Korea, who was diagnosed on the basis of serologic testing by hemagglutinin inhibition. We report here a 14-month-old boy who was taken supportive care and a 3-year-old girl who was taken amantadine and methyprednisolone pulse therapy. Both of them were admitted under the diagnosis of influenza-associated encephalopathy on the basis of reverse transcription-polymerase chain reaction of nasopharyngeal fluid and cerebrospinal fluidm, brain magnetic resonance imagings. The first case was confirmed by the identification of influenza A/H3N2 in the cerebrospinal fluid culture by RT-PCR for the first time in Korea.