Evidence-based medicine and clinical practice guidelines have become increasingly salient to the international health care community in the 1990s. Key issues in health policy in this period can be categorised as costs and access to care, quality of and satisfaction with care, accountability for value in health care, and public health and education. This paper presents a brief overview of evidence-based medicine and clinical practice guidelines and describes how they are likely to influence health policy. Evidence-based medicine focuses on the use of the best available clinical (efficacy) evidence to inform decisions about patient care; guidelines are statements systematically developed from efficacy and effectiveness research and clinical consensus for practitioners and patients to use in making decisions about appropriate care under different clinical circumstances. Both fields have developed methods for evaluating and synthesising available evidence about the outcomes of alternative health care interventions. They have clear implications for health policy analysts: greater reliance should be placed on scientific evidence, policy decisions should be derived systematically, and health care decisionmaking must allow for the active participation of health care providers, policy makers, and patients or their advocates. The methods and information generated from evidence-based guidelines efforts are critical inputs into health policy analysis and decisionmaking.