The prevalence intestinal of parasitosis was studied in a population of 150 children, which ages ranged from one to fourteen years, from Guazú-Cuá department of Paraguarí, which is an isolated community with very poor sanitary conditions. Feces from all 150 children were examined by the concentration and the Willis methods, and 94 percent of them had parasites (62.7 percent), 74 had only one parasites (78.7 percent) and 20 had two or more parasites (21.3 percent). Giardia lamblia was the most frequent parasite (22.0 percent) followed by Uncinaria (5.3 percent). The most frequent combination was that of Giardia and Uncinaria (5.3 percent). No age or sex preference for the parasites was detected. The high infestation rate suggests the need of improvement of the sanitary conditions and the education of the population