This paper reports on the results of a parasitological survey conducted among the Zoró Indians (Mato Grosso). From the total of 173 stool samples, 9 (5.2%) were positive for Ancilostomidae, 4 (23%) for Trichuris trichiura, 5 (2.9%) for Hymenolepis nana, 17 (9.8%) for Guardia lamblia, 5 (2.9%) for Balantidium coli, and 29 (16.8%) for Entamoeba hislolytica. The authors note the low prevalence of helminths and call attention for the possibilities of achieving control of these parasites among Amerindian communities by means of mass treatment. The authors also discuss the epidemiological implications of the practice of rearing mid pigs near the houses in the transmission of B. coli.