Between 1987 and 1988, 193 faecal specimens from children, with or without diarrhea, were submitted to enzyme immunoassay, polyacrylamide-gel electrophoresis and electronmicroscopy tests for virus detection. The positivity for Rotavirus, Adenovirus, Astrovirus, Calicivirus and Small Round Virus Particles (SRVP) was 11.3%, 3.1%, 2.1%, 1.0% and 4.1%, respectively, for the 97 children with acute diarrhea. Of the 96 children without diarrhea, 4.2% were positive for Rotavirus, 1.0% for Calicivirus and 7.3% for SRVP. Of 15 positive specimens for Rotavirus, 14 showed electrophoretic patterns proper to group A and 1 specimen of group C Rotavirus. The analysis of electrophorotypes demonstrated great heterogeneity of electrophoretic patterns and predominance of subgroup 2, "long". The association of virus, bacteria and parasites was present both in children with or without acute diarrhea.