The last two national surveys on intestinal parasitosis realized in Costa Rica (1982 and 1996) showed an impressive improvement of intestinal helmintiasis, with rates lower than 5%. Nevertheless, this problem is relegated to marginal communities, such as is demonstrated in this paper. Stool Samples of feces from 76 (56%) of the inhabitants of a squatter settlement near the Tiribí River, San José, Costa Rica were analyzed by direct wet smears, Kato, Stoll, and agar culture method to looking for Strongyloides. The forty-five percent of the people studied had at least one kind of intestinal parasites. The most frequently found parasites were Entamoeba coli (27%), Trichuris (18%), Ascaris (15%). These data prove that the problem of intestinal parasitosis is ongoing and is masked in national surveys that show a fictitiously low rates for the country.