A clinical analysis of 18 cases of E. coli septicaemia in children showed that 90% of cases were in infants aged up to 6 months, mainly in newborns. Half the cases developed in hospital. All strains with one exception were sensitive to gentamicin. In the whole complex of non-characteristic clinical manifestations loose stools were most frequent. In the laboratory investigations thrombocytopenia was the most characteristic abnormality. The mortality was 16.7%.