Vero cytotoxin (VT)-producing Escherichia coli O157 (O157 VTEC) were isolated from a raw beefburger obtained from a retail source linked to a small community outbreak of O157 VTEC infection in Wales. Strains from the meat and from seven of eight patients belonged to phage type 49 and were indistinguishable by their VT-type, plasmid content and hybridization with DNA of a VT-encoding phage from an O157 VTEC strain. This first report of the isolation of O157 VTEC from a beef product in Britain supports the view that there is a bovine reservoir for this organism.