Evaluation of the efficacy of influenza vaccines is essential for vaccine development. This study evaluated the neutralizing and hemagglutination-inhibition antibody response in subjects receiving the 2006-07 and 2007-08 seasonal influenza vaccines. ELISA-based microneutralization demonstrated a greater mean-fold increase and seroconversion rate than the hemagglutination-inhibition assay. The increase in the antibody titers against influenza H1 were higher than those against influenza H3 and influenza B, indicating that the H1 vaccine strain in the 2006-07 and 2007-08 seasons was more immunogenic. These data suggest that the neutralizing antibody response is a better measurement of influenza vaccine efficacy.