The aim of this study was to present preliminary experience with FDG PET/CT in pediatric oncology patients in National PET Center, Clinical Center of Serbia and to asses its impact on management of malignancies in children. 33 FDG PET/CT scans were performed on 30 pediatric patients. PET/CT imaging was performed for staging the disease, assessing therapy efficacy and diagnosing recurrent or metastatic disease. FDG PET/CT changed the stage of the disease in 60.6% (20/33) of the cases. 14 patients were down-staged after PET/CT, mostly patients with Hodgkin's disease, were in 7/10 cases PET/CT showed no activity in residual masses. Six scans led to upstage of the disease. In three cases PET/CT did not change the stage of disease, but has showed new distant metastases. In conclusion, FDG PET/CT showed important role in managing pediatric patients with different malignancies and was useful complementary diagnostic tool to conventional imaging methods.