Children with cancer are at a significant risk of having nutritional difficulties as a result of their underlying condition and the adverse effects of multimodal therapy. Nutritional status (NS) can impact a variety of clinical outcomes, including overall survival (OS) and eventfree survival (EFS), therapy tolerance, infection risk, and quality of life (QoL). However, the role of diet in cancer children is largely underappreciated. This review focuses on NS changes in children undergoing cancer therapy. In the paediatric cancer population, there is currently a lack of a systematic strategy and conventional recommendations for nutritional management. According to a review of the literature, it is critical to define the NS and handle any changes in a timely way to ensure optimal growth and development.