E. coli was considered as the possible aetiologic agent in 16 cases (5.7%) of 283 hospital admissions for diarrhoea. One invasive strain was isolated from a case with exudative diarrhoea. Four heat-labile (LT) enterotoxin-producing strains were found in relatively mild cases of diarrhoea. Eleven strains belonged to "classic" pathogenic serotypes (EPEC); 9 of these were endemic cases and 2 associated with travel. Of the latter, 1 strain (078) was also found to produce heat-stable (ST) enterotoxin detectable by infant mouse assay. Although EPEC are now found much less frequently than 20 years ago, E. coli as a whole may still be the most common bacterial aetiology of childhood diarrhoea in Finland.