To map out genomic differences between highly pathogenic Yersinia enterocolitica WA-314C biogroup 1B, serotype O:8 strain and low-pathogenic Y. enterocolitica Y-108C biogroup 4, serotype O:3 strain we have applied a method of suppression subtractive hybridization (SSH). In total, 428 WA-314-specific and 83 Y-108-specific sequences were uncovered by SSH. Among them were DNA fragments with similarity to known genes from several groups: (1) genes involved in O-antigen biosynthesis, (2) host-specific restriction-modification systems, (3) systems of iron and heme acquisition and storage, (4) flagellar biogenesis genes, (5) putative virulence factors, (6) drug resistance genes, and (7) mobile elements. Mapped out genomic differences may be applied in identification and development of novel therapeutic strategies for the treatment of enteropathogenic Yersinia.