Seventy random samples of raw and pasteurized milk (35 of each) were collected from different localities in Assiut City, Egypt, and examined bacteriologically for the presence of Yersinia enterocolitica. The samples were collected in summer months, 2012. The results revealed that Yersinia enterocolitica was detected in 20.0 and 5.7 % of the examined marketable raw and pasteurized milk samples, respectively. The virulence of the recovered isolates of Yersinia enterocolitica was tested by using virulence test (Guinea pig conjunctivitis) and revealed that non of the isolated strains harbouring virulence determinants (Avirulent strain).