This study showed different frequencies of intestinal parasitosis (giardiasis and helminthiasis) among children in day-care centers and junior and high schools (public and private). The survey involved 199 individuals, 96 belonging to public schools and 103 to private institutions. The frequency of giardiasis in public institutions was shown to be greater than in private institutions. Regarding helminthiasis, frequencies were similar among day-care centers, but greater for public schools in comparison to private institutions. When levels of socio-economic status, education, basic sanitary conditions and hygiene were analyzed as determinants of intestinal parasitosis, it became evident that greater frequency of giardiasis and helminthiasis occurred among children from low-income families and those whose parents had low levels of education. The source of vegetables was also a significant factor in determining such parasitosis.