From 1995 through 1996, 163 fecal specimens of children aged under 5 years were analysed, 91 being from diarrhea feces and 72 without diarrhea. The material was collected in transport medium and submitted to the enrichment procedure at 4 degrees C for 7 days. For the primary isolation starch ampicillin agar was used and incubated at 35 degrees C for 18 to 24 hours. Twenty (20.9%) from the following specimens were isolated: Aeromonas (A.) caviae (7.7%), A. salmonicida salmonicida (6.6%), A. sobria (4.3%), A. hydrophila (2.2%) and Salmonicida achromogenes (1.1%). No Aeromonas spp. was isolated from the 72 control subjects. The Aeromonas spp. susceptibility to antimicrobial was greater with ciprofloxacin, being this susceptibility gradually diminished with chloranphenicol, gentamicin, ampicillin and erythromycin.