In resource-rich countries, 5-year survival rates for children with cancer approach 85%. This impressive statistic is largely the result of integrating research with clinical care. At the core of this endeavor are multiagent combination chemotherapy and supportive care agents (CASCA). Most CASCAs belong to the class of sterile injectable drugs, which make up the backbone of many proven and life-saving pediatric oncology regimens. There are few if any alternative agents available to treat most life-threatening childhood cancers. In the United States, shortages of CASCAs are now commonplace. The consequences of drug shortages are far reaching. Beyond the economic costs, these shortages directly affect patients' lives, and this is especially true for children with cancer. Drug shortages in general and shortages of CASCAs specifically result in increased medication errors, delayed administration of life-saving therapy, inferior outcomes, and patient deaths. One way to mitigate drug shortages is to adopt an essential medicines list and ensure that these medications remain in adequate supply at all times. We argue for creation of a CASCA-specific essential medicines list for childhood cancer and provide ethical and policy-based reasoning for this approach. We recognize that such a call has implications beyond pediatric cancer, in that children with other serious disease should have an equal claim to access to guaranteed evidence-based medicines. We provide these arguments as an example of what should be claimed for medical indications that are deemed essential to preserve life and function.