Outbreaks and sporadic cases of Escherichia coli O157 human infection are noticed since 1982 worldwide. Although the percentage of infected animal (bovine) reservoir in Poland is low (0.73%) human illness could develop. Shiga toxigenic strains can cause severe gastrointestinal disease with hemolytic-uremic syndrome and thrombocytic thrombophlebitic purpura with serious sequelae. For this reason we have examined 28 patients hospitalized with bloody diarrhoea for E. coli O157:H7 infection using Multiplex PCR Test. Only one person (0.036%), a 78-year old woman, presented characteristic symptoms (three days lasting bloody diarhoea, abdominal crumps, fever, neurological symptoms), endoscopical findings (marked oedema, facile haemorrhage, longitudinal ulcer-like lesions) and positive results on PCR. Despite low incidence of E. coli O157 infection doctors should be aware that such infection in Poland is likely to happen.