The workers' compensation system in the United States, comprised of independent state based and national programs for federal workers, covers approximately 127 million workers and has evolved and grown since its inception in 1911. Coverage has significantly broadened in scope to allow for the inclusion of most occupational injuries and illnesses. The cost of workers' compensation care has also increased. Some of the cost drivers have been identified,and various approaches have been taken to address medical cost containment. There is a need to balance cost control with ensuring benefit adequacy and quality of medical care. It is likely that managing workers' compensation costs will continue to be a challenge in the foreseeable future. The cost of workers' compensation care affects all stakeholders including workers, employers,providers, state workers' compensation regulators, legislatures,and insurers. A continued commitment to quality, accessibility to care, and cost containment, and being alert to emerging issues that can affect these elements, will help ensure that workers are afforded accessible, high quality, and cost-effective care.