Three hundred of 381 subjects examined from the Camiri, Boyuibe and Gutierrez areas (Santa Cruz Department) harboured one to six species of intestinal helminths and/or protozoa. High infection rates were found in Camiri in the orphanage (43 of 44 persons) and in the Military Hospital (10 of 10 persons), as well as in Itanambicua (97.4%), a rural community close to the city (38 of 39 persons). No significant differences were noted between the overall parasitic prevalences observed in rural and urban environments, but the frequency of species was different. Indiscriminate defaecation, the habit of living in close association with animals, overcrowding, and especially lack of health education, are some of the factors responsible for the parasitic situation observed.