Influenza virus is a major cause of respiratory infection in the epidemic season. Especially, the elderly with underlying health problems are at increased risk for complications of influenza. The objective of this study was to investigate that influenza vaccination can reduce the hospital admission rate related to the respiratory diseases. This study was a retrospective study of two age groups, who are the healthy children aged 6 months to 9 years (n=237) and the adults aged over 20 years with respiratory disease (n=327). The vaccinated groups were compared to the controls that were matched in sex and age. The children were vaccinated in winter season of 1995-96 and the adults were vaccinated in 1996-97. The efficacy of influenza vaccine was evaluated with the number of outpatient visits in children group, the admission rate and the mean admission days in both children and adult group. As results, there were not significant differences between the vaccinated and the control group of children. In the elderly over 61 years, however, the influenza vaccination can reduce the admission rate $(8.9\%;vs.;25.6\%,;p<0.05)$ and the mean admission days (1.3 vs. 3.8 days, p<0.05) compared to the control. In conclusion, influenza vaccination can effectively reduce the events related to respiratory infection in the elderly than the children. The elderly should be recommended for influenza vaccination.