Escherichia (E.) coli is commensal bacteria found in the intestine; however, some pathogenic strains cause diseases in animals and humans. Although E. coli does not typically produce hydrogen sulfide (H2S), H2S-producing strains of E. coli have been identified worldwide. The relationship between virulence and H2S production has not yet been determined. Therefore, characteristics of H2S-producing isolates obtained from swine feces were evaluated including antibiotic resistance patterns, virulence gene expression, and genetic relatedness. Rates of antibiotic resistance of the H2Sproducing E. coli varied according to antibiotic. Only the EAST1 gene was detected as a virulence gene in five H2S-producing E. coli strains. Genes conferring H2S production were not transmissible although the sseA gene encoding 3-mercaptopyruvate sulfurtransferase was detected in all H2S-producing E. coli strains. Sequences of the sseA gene motif CGSVTA around Cys238 were also identical in all H2S- producing E. coli strains. Diverse genetic relatedness among the isolates was observed by pulsed-field gel electrophoresis analysis. These results suggested that H2S-producing E. coli strains were not derived from a specific clone and H2S production in E. coli is not associated with virulence genes.