This paper describes the effects of some antimicrotubular drugs (mebendazole, flubendazole, thiabendazole, colchicine, griseofulvin, vinblastine and isopropyl-N-phenylcarbamate or IPC) on growth and viability of Trichomonas vaginalis. Among the inhibitors tested, mebendazole and flubendazole irreversibly inhibit protozoa growth at low concentration (greater than or equal to 1 microgram/ml), while colchicine and griseofulvin act at higher concentrations and thiabendazole and IPC are ineffective. In order to explain mechanism of action of these drugs, some microtubule-correlated functions such as shape modification and mitotic index were studied. Our results support the hypothesis that the main targets for these compounds are the cytoplasmic microtubules of Trichomonas vaginalis.