Abstract: Trichomonas vaginalis obtaincd from infected paticnts were cultivated for 48 hours. The cells revealed by SEM were ovoid or pear-shaped. Four anterior flagella emergcd from the periflagellar canal very close to one another. The posterior flagellum cmerged, independently of the anterior flagella from the dorsal part of the canal. The point of emergence of posterior flagellum was separated from anterior flagella by thc wall of thc periflagcllar canal. The posterior flagellum extended to the posterior end of the cell along the left side of the undulating membrane, which was a wave-like membrancous structure extending outside the body from the cytoplasm and the outer membrane. A comparison of the members of a population rcvcals variability in length of the undulating membrane. In the outer margin of the undulating mcmbrane.no accessory filament was seen. The axostyle of the organism projeeted from the posterior end of the cell.