There was determined the Trypanosoma specie that caused Trypanosomiasis for livestocks in Vietnam, the result was obtained: the Trypanosoma parasitologic specie was Trypanosoma evansi. Applying some parasitological techniques for the diagnosis of trypanosomiasis in the laboratory such as direct microscopic examination (blood sampling), stained thick smears, animal inoculation...to determine the prevalence on some livestocks in the investigated places. The following results were shown: buffaloes, bovines, goat, horses, porcine in the investigated provinces were infected by Trypanosoma evansi with different prevalence, vacillating from 0.99 percent to 20.83 percent. In that results, the prevalence increased in accordance with the age of buffalos and bovines. The prevalence performed high in autumn, lower in Spring. However, the incidence was highest performance in Winter and lowest in Summer.