Foods of bovine origin have been linked to human disease outbreaks caused by Escherichia coli O157:H7 and may be linked to the more common sporadic cases as well. In this study, E. coli O157:H7 from the bovine reservoir (22 isolates: 12 from dairy and 10 from beef breed cows)and from human patients (50 isolates from sporadic human infections) were compared using Shigalike toxin genotypes, plasmid profiles, and DNA restriction fragment length polymorphisms identified with a bacteriophage λ probe (λ-RFLP). Twenty-three λ-RFLPprofiles, 4 Shiga-like toxin genotypes, and 8 plasmid profiles were identified among the isolates tested. Together the typing methods distinguished 43 strains, of which 3 were isolated from both humans (5 isolates) and cattle (6 isolates; 5 from dairy herds). These data demonstrate the value of λ-RFLP as a means of strain identification for E. coli O157:H7.