peer reviewed ; Enterohemorrhagic Escherichia coli (EHEC), enteropathogenic E. coli (EPEC) and Shigatoxigenic E. coli (STEC) are carried by healthy adult cattle and even more frequently, young calves in their intestinal tract, especially at the height of the recto-anal junction. The purpose of the present study was to assess the presence of ten EHEC, EPEC and/or STEC O serotypes (O5, O26, O80, O103, O111, O118, O121, O145, O157, O165) in calves sampled by recto-anal mucosal swabs (RAMS) in three dairy farms in Belgium. A total of 233 RAMS were collected on 3 consecutive times from healthy <6-month-old Holstein-Friesian calves and submitted to a PCR targeting the eae, stx1 and stx2 genes after non-selective overnight enrichment growth. The 148 RAMS testing positive were streaked on four (semi-)selective agar media: of the 2146 colonies tested, 294 from 69 RAMS were PCR-confirmed as EHEC, EPEC or STEC. The most frequent virulotype was eae+ EPEC and the second one was stx1+stx2+ STEC while the eae+stx1+ and eae+stx1+stx2+ virulotypes were the most frequent amongst EHEC. The majority of EHEC (73%) tested positive for one of the 5 O serotypes detected (O26, O103, O111, O145, or O157) vs. 23% of EPEC and 45% of STEC. Similarly, more RAMS (73%) harbored EHEC isolates positive for those 5 serotypes, than EPEC (53%) or STEC (52%). This survey confirms that (i) healthy young dairy calves are asymptomatic carriers of EHEC and EPEC in Belgium; (ii) the carrier state rates, the virulotypes and the identified O serotypes differ between farms and in time; and (iii) a majority of EPEC belong to still unidentified O serotypes