Anti-trichomonad IgA antibodies were estimated by enzyme-linked immunosorbent assay (ELISA) in serum and vaginal secretions of 25 symptomatic and 25 asymptomatic Trichomonas vaginalis positive patients before and after treatment and in 25 age-matched controls. Significantly higher levels of antitrichomonad IgA antibodies were found in T. vaginalis positive patients when compared to control subjects, especially in vaginal secretions. In addition, a significant decrease in these antibodies was observed after treatment, which was more pronounced in vaginal secretions. It seems that anti-trichomonad IgA antibodies in serum and more so in vaginal secretions are directly related to and specific to the presence of T. vaginalis in the urogenital tract.