An infection with T. vaginalis in male patients is difficult to diagnose in case of latent or asymptomatic trichomoniasis. This infection is caused by the round forms of T. vaginalis, which are significantly more frequent in male patients, than trophozoites. Trichomonas vaginalis round forms called pseudocyst due to their specific biological properties are difficult to observe with actually used techniques. It was shown, that round forms of T. vaginalis may be detected by Giemsa modified technique and modified survival technique employing acridine orange. Therefore routine diagnosis of trichomoniasis included direct examination of the discharge from urethra, cultures and survival technique employing acridine orange. In the problematic cases, especially in male patients with the latent or asymptomatic trichomoniasis, full range of methods should be used to examine specimen collected from the each part of the urinary tract.