Background and Objective: Considering the relatively wide application of ceftriaxone in pediatric infectious diseases and its side effects, this study was done to determine gallblader sonographic abnormality following ceftriaxone treatment in children.

Materials and Methods: This descriptive cross- sectional study was carried out on 60 patients age 1 month up to 12 years in Besat hospital, Hamadan, Iran during 2007. The sonographic abnormal finding of gallbladder before ceftriaxone therapy and 5 days after therapy were recorded. In case of any abnormality in gallblader sonography was repeated twice a week in the first two weeks and afterward once a week up to disappearance of abnormalities.

Results: Gallblader sonographic abnormality were observed in 10 cases (16.5%). Out of them, 8 and 2 patients had bile stone and bile sludge, respectivley. The patients did not show any clinical manifestations. There was no relation between age and sex with abnormal findings. Gallblader abnormality completely were disappeared in the worst cases by sixteen days.

Conclusion: This study showed that the incidence of either gallstone or biliary sludge after treatment with ceftriaxone was 16.5% which is relatively similar to other studies.