OBJECTIVE: To describe some of the unique aspects of medical care offered under workers' compensation insurance systems and discuss the major policy considerations relevant to health services researchers undertaking investigations in this area. BACKGROUND AND FINDINGS: State-based workers' compensation (WC) insurance systems requiring employers to pay for medical care and wage replacement for workplace injuries and illnesses were first developed between 1910 and 1920 in the United States. Employers are generally required to purchase state-regulated workers' compensation insurance that includes first-dollar payment for all medical and rehabilitative services and payment of lost wages to workers with work-related illness or injury. Injured workers have variable but usually limited latitude in choosing their health care provider. Employers and workers' compensation insurers have incentives for controlling both the cost of medical care and lost wages. CONCLUSION: The major policy issues in WC medical care--the effect of patient choice of provider and delivery system structure, the ensuring of high-quality care, the effect of integrating benefits, and investigation of the interrelationships between work, health, and productivity--can be informed by current studies in health services research and by targeted future studies of workers' compensation populations. These studies must consider the extent of patient choice of physician, the regulatory environment, the unique role of the workplace as a risk and modifying factor, and the complex interaction between health and disability insurance benefits.