Positron emission tomography (PET) is a novel non invasive functional imaging modality that is increasingly used for the primary staging of lymphomas and assessment of therapeutic response. This review evaluates the published reports of its use in childhood lymphomas, particularly in the primary staging, response assessment and monitoring after completion of treatment. Specific attention is focused on the clinical circumstances in which FDG PET is most likely to have an impact on management and some indications for its use in childhood lymphomas are suggested.