Abstract: The objective of this study was to identify the bacterial causative agents associated with the incidence of infectious disease cases in a sheep farm in Inner Mongolia, and to characterize the virulence and antimicrobial resistance patterns of the isolates. Clinical samples were recovered from the diseased sheep to isolate bacterial strains with eosin methylene blue (EMB) agar. Subsequently, the isolates were phenotypically and molecularly identified to genus level, and their virulence and antimicrobial resistance patterns were characterized. Two gram-negative strains with typical growth features of Escherichia coli in EMB agar were obtained. The isolates were confirmatively identified as Escherichia coli by biochemical reactions and 16S rDNA PCR and sequence analysis. Both of the isolated strains showed pathogenicity to experimental animals and exhibited resistance to several antimicrobial agents commonly used in veterinary clinic. Our results demonstrated the prevalence of the antibiotic resistant and pathogenic Escherichia coli in this sheep farm.