The Children’s Oncology Group (COG), a National Cancer Institute supported clinical trials group, is the world’s largest organization devoted exclusively to childhood and adolescent cancer research. The COG unites more than 10,000 experts in childhood cancer at more than 200 leading children’s hospitals, universities, and cancer centers across North America, Australia, and New Zealand in the fight against childhood cancer. Today, more than 90% of 16,000 children and adolescents diagnosed with cancer each year in the United States are cared for at Children’s Oncology Group member institutions. COG’s unparalleled collaborative efforts provide the information and support needed to answer important clinical questions in the fight against cancer. The Children’s Oncology Group has nearly 100 active clinical trials open at any given time. These trials include front-line treatment for many types of childhood cancers, studies aimed at determining the underlying biology of these diseases, and trials involving new and emerging treatments, supportive care, and survivorship. The Children’s Oncology Group research has turned children’s cancer from a virtually incurable disease 50 years ago to one with a combined 5-year survival rate of 80% today. Our goal is to cure all children and adolescents with cancer, reduce the short and long-term complications of cancer treatments, and determine the causes and find ways to prevent childhood cancer.