The purpose of this study was to evaluate the infections caused by Yersinia enterocolitica and Y. pseudotuberculosis strains and to determine the in vitro antibiotic susceptibility of these bacteria. The study was performed on 34 Yersinia strains isolated from various specimens sent to the laboratory in a five-year period (January 1997 - June 2001) Thirty (88%) of 34 strains were Y. enterocolitica and four (12%) were Y. pseudotuberculosis. Most of the Yersinia strains were isolated from the Pediatric Clinic (53%), and their origin were gastrointestinal (29%) and wound infections (27%). In antimicrobial susceptibility tests with microdilution method, the most effective agents against the strains of the Yersinia were imipenem (100%), ciprofloxacine (82%), amikacine (82%), gentamicin (76%) and nitrofurantoine (75%). This study underlines the importance of Yersinia infections and their antimicrobial susceptibility patterns, a subject neglected in this country.