We measured specific IgE antibodies to mites and Japanese cedar pollen (JCP) in a general population aged from 18 to 99 years by fluorescence enzyme immunoassay and analyzed the relationship of antigen-specific IgE antibody production to aging. The incidence of mite antibody carriage gradually decreased in proportion to age from 26.7% at 18 to 19 years of age to 15.9% for the 60 to 69 age group and then decreased markedly in the subjects aged 70 and over. A similar tendency was found with regard to JCP antibody positivity. The highest levels of antibodies to both mites and JCP were found in young adults, and these levels decreased with age. There was a significant negative correlation between the mean relative fluorescence unit value for specific IgE antibodies and age (mite antibody: r = -.957 and JCP antibody: r = -.954). No significant correlation was found between mite antibody levels and JCP antibody levels in the individual subjects.