One hundred sixteen faeces samples from adult pigs and piglets with or without the diarrhoea syndrom were analyzed. Ninety nine strains of E. coli were isolated, some of them showed alpha or beta haemolysis or enterohaemolysin; the majority of these were isolated from piglets suffering diarrhoea. The presence of F4 (K88) fimbriae was confirmed in 5 piglets with diarrhoea and the presence of F5 (K99) was confirmed in one case. One F4 (K88) strain was isolated from an adult and healthy sow, which was the mother of the piglets. All fimbrial strains, but two, were haemolytic, 3 of them were alphahaemolytic and 2 were enterohaemolysin producers.