Malnutrition is often seen at the point of diagnosis in childhood malignancy or may develop during the course of treatment. Strategies for optimal diagnosis and management of nutritional problems in children with cancer are limited in the published literature. Identification of children who may be malnourished or at nutritional risk can be achieved through improved approaches for risk stratification and classification. Once recognised, various strategies have been demonstrated to reduce malnutrition, minimise side effects of treatment and improve survival. Novel approaches in vivo and adult oncology populations provide future avenues for investigation.