The immune response to vaccination with SolcoTrichovac, a vaccine against trichomoniasis, was studied in 97 women with trichomonad colpitis. In almost all the cases an increase in specific serum agglutinins was found. The geometric mean of these titres increased from 1:56.4 before the vaccination to 1:320 after the vaccination, and it was still 1:140 1 year later. The dynamics of the serological immune response correlated with the clinical efficacy of this new vaccine.