We describe our initial experience with integrated whole-body Fluor-18-Fluordesoxyglucose-PET/MR imaging in children in a retrospective study of all 18F-FDG-PET/MR at our institution. 51 studies were carried out in 41 children (34 girls, 17 boys) with a mean age of 10.16 years (10 months-24 years). Primary diagnosis included rhabdomyosarcoma (n=18) and Osteosarcoma (n=5). The majority of studies (n=29, 57.9%) were performed for treatment response/restaging. All studies were diagnostic (technical success rate 100%). The mean effective dose was 5.25 mSv (2.1-11.5 mSv). Mean total imaging time was 80 minutes (42-138 minutes). Thirty-eight (74.5%) cases had an average of 2.2 additional MR sequences. 18F-FDG PET/MR is technically feasible for the evaluation of oncologic processes in children at a fraction of the radiation dose.