Advancements in cancer treatment have improved survival rates for children, but all therapies carry the risk of toxic effects, impacting various organ systems. Radiologists play a key role in identifying these complications, which can arise during diagnosis, initial treatment, or after therapy completion. Early complications include oncologic emergencies like superior vena cava syndrome, metabolic disturbances, and infections. Later effects include leukoencephalopathy, cataracts, cardiomyopathy, hepatic fibrosis, renal dysfunction, scoliosis, hypothyroidism, and secondary malignancies. Awareness of these issues enhances patient surveillance and timely intervention, improving long-term outcomes and quality of life.