A study on intestinal parasitism was conducted among 401 children admitted in the Pediatric Teaching Hospital of Cerro, from May to June, 1999. To this end, a representative, randomized and stratified sample by service was taken. 3 samples of feces per child were collected, preserved in formaldehyde, and processed by 3 parasitological methods. There was an intestinal parasitism prevalence of 15% at the hospital and there were no differences between the stratum of children admitted in Gastroenterology and the rest of the services as regards commensals and parasites in general (p > 0.05); however, commensals predominated in the second group (p < 0.01) The intestinal coccidia, Cryptosporidium parvum and Cyclospora cayetanensis prevailed in the Gastroenterology service over the rest of the services (p < 0.01). The age group over 4 (school children) was the most affected, both by protozoa and commensals (p < 0.01), excepting Cryptosporidium parvum that affected the infants more (p < 0.05). The analysis of some epidemiological antecedents showed that those children eating fruit without peeling and washing them, having vegetables withouth washing them first and walking barefooted were more prone to infection (RR > 1). A higher frequency of infection due to intestinal parasites was found among those living in rural areas, drinking well or river water, and defecating in latrines or in the open air (RR > 1). These results suggested that in spite of the existing knowledge of the epidemiological and risk factors, the intestinal parasites continue affecting the child population