Shigella species may lead to large epidemics owing to their low infective doses and frequent transmission from person to person with high secondary attack rates. Shigella sonnei is one of the most prevalent causative agent of infectious gastroenteritis in developing and developed countries and it is the most frequently reported Shigella serotype from Turkey in recent years. The aim of this study was to determine the types of S. sonnei strains isolated in different provinces of Turkey [in Marmara earthquake regions (Izmit, n=5; Adapazari, n=6; Yalova, n=2) in 1999 and in Ankara (n=17) in 1997, 2000 and 2001] according to their antimicrobial resistance and pulsed field gel electrophoresis (PFGE) patterns. All isolates were found sensitive to gentamicin, ceftriaxone, imipenem, nalidixic acid and ciprofloxacin. Twenty three (76.6%) of isolates were found resistant to streptomycin, 21 (70%) to trimethoprim-sulfamethoxazole, 20 (66.6%) to tetracycline, 6 (20%) to ampicillin, 3 (10%) to ampicillin/sulbactam and 1 (3.3%) to chloramphenicol. Three (%10) isolates were detected as intermediate susceptible to tetracycline and cefoperazone, while four isolates (13.3%) were susceptible to all antimicrobial agents tested. A total of nine different patterns were obtained according to antimicrobial resistance patterns. PFGE was performed by Xbal restriction enzyme. Isolates were grouped into A (n=24) and B (n=6) main PFGE types and into 13 closely or possibly related types. A total of 15 different PFGE patterns were identified among the isolates. It was determined that isolates from the same clone disseminated in Ankara during the years 2000-2001. Overall, different clones of S. sonnei strains were in dissemination in the provinces included. This study indicated that different S. sonnei clones were in circulation in Turkey and these results constitute the basic molecular preliminary data for the National Enteric Pathogens Laboratory Network in Turkey.