ABSTRACT Trichomonas gallinae (Rivolta, 1878) is a parasitic protozoan of the upper digestive tract and various organs of different avian groups, being common among the Columbids, was isolated described and its prevalence studies in the Southern Brazilian State, Rio Grande do Sul. The morphology study of the live specimens done by examination of fresh and stained specimens, showed that the T. gallinae isolated has the same morphological characteristics as the upper digestive tract trichomonads previously described by other authors