Summary Faecal material from children aged zero to 5 years old with diagnosed GEA at one hospital in Manaus was studied through electron microscopy and enzime immunoassay. Samples were collected before any medical treatment was to be applied at the hospital. Out of 29 cases studied 12 showed positivity for rotavirus (41,4%). Out of the 29 cases studied 48,3% were treated with isolated rehydration, 31,0% with antibiotic therapy and 20,7% with chemotherapy. Out of the 12 positive cases 3 were treated with antibiotics and 3 with chemotherapy. Greater frequency of rotavirus was found to occur between zero to 12 months old children. Within this range of age the greater number of GEA and rotavirus cases was detected between the 7th and the 12th month.