In this study, the occurrence of Yersinia enterocolitica on pig carcasses was compared to the occurrence of Campylobacter spp., and to the numbers of aerobic micro-organisms, coliform bacteria, thermotolerant coliform bacteria, and Escherichia coli before and after blast chilling. Y. enterocolitica O:3/biovar 4 was isolated from five (8.3%) of 60 carcasses before blast chilling, and also from five of them 1 h after blast chilling. Therefore this procedure does not seem to have a significant effect on the occurrence of pathogenic Y. enterocolitica on pig carcasses. Y. enterocolitica O:9/biovar 2 was isolated from a pig source in Norway for the first time when this sero/biovariant was isolated from one of the carcasses before blast chilling. Campylobacter spp. was isolated from 34 (56.7%) of 60 carcass samples before blast chilling. After blast chilling Campylobacter spp. was isolated from only one (1.7%) of the 60 carcasses. There was a significant decrease of the numbers of coliform bacteria, thermotolerant coliform bacteria and E. coli after blast chilling. The number of aerobic micro-organisms did not decrease after this step. In contrast to the drastic decrease in the occurrence of campylobacter-positive carcasses and the significant decrease of the numbers of coliform bacteria, thermotolerant coliform bacteria and E. coli, blast chilling does not seem to have a significant effect on the occurrence of human pathogenic Y. enterocolitica on pig carcasses.