The rate of publication of clinical practice guidelines for the management of common medical illnesses continues to accelerate. The appropriate dissemination and uptake of high quality practice guidelines can synthesize evidence, improve patient outcomes and enhance the efficiency of health care delivery. However, the methodological rigour and relevance of the growing number of publications labelled ’clinical practice guidelines’ vary widely. Health care payers, providers and advocates must learn to appraise and interpret guideline recommendations critically. A simple and practical nine-question approach to evaluating the quality, relevance and effectiveness of clinical practice guidelines is presented.