The prevalence of Yersinia enterocolitica and Yersinia pseudotuberculosis was determined in slaughter pigs from 47 farms in Latvia. Tonsils from 404 pigs representing farms from four geographical areas (Kurzeme, Latgale, Vidzeme, and Zemgale) were collected at slaughter in 2007 and 2008. The prevalences of Y. enterocolitica and Y. pseudotuberculosis were 35 and 3%, respectively. All Y. enterocolitica isolates belonged to bioserotype 4/O:3. Y. enterocolitica was recovered from 35 of 47 pig farms, and Y. pseudotuberculosis was found on 6 farms. The prevalence of Yersinia was highest in Latgale (90%) followed by Kurzeme (39%), Zemgale (33%), and Vidzeme (21%). Y. enterocolitica 4/O:3 was sensitive to amoxicillin-clavulanic acid, aztreonam, cefotaxime, ceftriaxone, chloramphenicol, ciprofloxacin, nalidixic acid, trimethoprim, and trimethoprim-sulfamethoxazole and resistant to ampicillin, cephalothin, erythromycin, streptomycin, sulfamethoxazole, and tetracycline. Y. pseudotuberculosis exhibited resistance to erythromycin and sulfamethoxazole but not to the other antimicrobial agents tested. The results of this study are a valuable starting point for monitoring the prevalence and antimicrobial resistance of Yersinia in pigs in Latvia.