The epidemiology and antibiotic sensitivity of Shigella species is changing worldwide. The present study surveyed the changing clinical and epidemiological characteristics and antibiotic susceptibility of Shigella gastroenteritis in Hacettepe University Ihsan Dogramaci Children's Hospital Diarrhoea Training and Treatment Unit between 1987 and 1994. Among 19 812 diarrheal admissions, 618 (3.2%) patient Files with Shigella gastroenteritis were reviewed retrospectively. Shigella soneii has been the commonest isolate (64%) since 1987 followed by S. flexineri (30%), S. boydii (5%) and S. dysenteriae (1%), the latter having not been isolated since 1990. The isolate rate of S. sonnei has increased whereas the isolation rate of S. flexineri has decreased concomitantly since 1987 (r= -0.94; P < 0.001). The majority of cases (365/618, 59%) were between 1 and 5 years of age. On admission bloody diarrhea was present in 36%, seizures in 3% and mild-moderate dehydration in 11% of cases. No case had severe dehydration. Only six patients (1%) were hospitalized. No deaths were recorded. The resistance rate for trimethoprim-sulfamethoxazole has increased from 27% in 1990 to 66% in 1994 (P < 0.05) while the resistance rate for ampicillin has decreased from 81% in 1987 to 32% in 1993 (P < 0.001). Shigella flexineri was found to have higher resistance rates to ampicillin, sulbactam-ampicillin, chloramphenicol and gentamicin than S. sonnei. Changing Shigella sp. over the years may be the reason for the mild course of Shigella gastroenteritis. Further regional epidemiological studies are necessary to develop more appropriate management guidelines, especially in developing countries.