In order to investigate pathogenic genes and genetic relationships of Y. pseudotuberculosis strains, We isolated 9 strains of Y. pseudotuberculosis from 380 spring water sites in Seoul from 2000 to 2003. All isolates were distributed to the northeast area in Seoul. The isloates were analyzed for chromosomal virulence gene (inv) and plasmid-borne genes (yadA and lcrF) using PCR to assume pathogenicity. As a result, all isolates were positive for the inv gene, but only five isolates (55.6%) were positive for the yadA and lcrF genes. RAPD and PCR-ribotyping were tested and all isolates were grouped with 90% similarity. RAPD revealed 4 clusters and PCR-ribotyping revealed 2 clusters. The result of this experiments confirmed the view that RAPD had better powerful discrimination than PCR-ribotyping and RAPD typing was effective to distinguish between various strains of Y. pseudotuberculosis from spring water.