Verotoxigenic E. coli or VTEC (rev. Karmali 1989) are endemic in bovines since 1967 in Belgium. The great majority of these strains produce an enterohemolysin. This property is useful to distinguish VTEC strains from other types of E. coli. Among calves suffering from diarrhoea or dysentery, VTEC strains belonging to serogroups 05, 08, 020, 026, 0111 and 0118 are very frequently isolated. They attach to gut epithelium and efface the micro-villi. Among bovines which are asymptomatic carriers, VTEC strains belonging to others serogroups are observed: 022, 025, 0116, 0121, O157 and 0171. We propose that the VTEC strains isolated from healthy bovines do not possess the attaching-effacing properties.