The importance of evidence in teaching and in support of clinical decisions is well established in health care, including dentistry. Defence of clinical decisions increasingly requires reliable data or evidence to support the stance taken. Assistance in finding the best evidence comes from a variety of sources, including computerised databases, journals, continuing education meetings, and study clubs. The randomised controlled trial heads the hierarchy of research designs on which evaluation of evidence is based; anecdotally based evidence and individual case studies are the least preferred study designs. Evaluation of a study requires a number of questions to be asked to determine how the study was performed, and whether it applies to a clinical situation. These questions relate to how the study was carried out, whether controls were used, were the results likely to be valid, and was statistical and clinical significance present. Quackery, pressure from consumers, and legal considerations have contributed to an increase in the importance of evidence-based practice. The benefits, however, of evidence-based practice are that treatment decisions are easier to justify, especially when there is a complaint or a dento-legal issue, and the personal satisfaction that patients are being offered the best treatment.