one hundred and thirty cases of diarrhea and 43 age-matched controls, 0 to 5 years old, were studied in a pediatric outpatient unit from a poor peri urban area of porto velho, rond？nia. eighty percent of diarrheal cases were observed in the groups under 2 years of age. rotavirus (19.2%) was the most frequent enteropathogen associated with diarrhea, followed by shigella flexneri (6.15%) and s. sonnei (1.5%) and salmonella sp. (6.9%). four cases of e. coli enterotoxigenic infections (3.1%), e. coli enteropathogenic (epec)(2.3%) one case of e. coli enteroinvasive infection (0.8%) and one case of yersinia enterocolitica (0.8%) were also identified. mixed infections were frequent, associating rotavirus, epec and salmonella sp. with entamoeba histolytica and giardia lamblia.