Low back pain has long been described as a challenge for both primary care physicians and specialists. Management of low back pain has also been criticized as frequently arbitrary, inappropriate, or ineffective. Contributing factors have been an inadequate evidence base and a need for more rigorous appraisals of the available literature. Evidence-based medicine, an approach to clinical problem solving, is predicated on the premise that high-quality health care will result from practices consistent with the best evidence. In contrast to the traditional medical paradigm that placed a heavy reliance on expert opinion, authority, and unsystematic clinical observations, evidence-based medicine emphasizes the need for rigorous critical appraisals of the scientific literature to inform medical decision making. Evidence-based medicine places strong weight on the requirement for valid studies, particularly randomized controlled trials, to appropriately evaluate the effectiveness of health care interventions. Because of the rapidly increasing volume of medical literature, however, most clinicians are unable to keep up-to-date with all the new data. Two types of preprocessed evidence that can aid busy clinicians in medical decision making are systematic reviews and evidence-based clinical practice guidelines. Like primary studies, systematic reviews and clinical practice guidelines must adhere to high methodologic standards to reduce error and bias. As in other areas of medicine, the approach to the management of low back pain has been positively affected by the availability of more clinical trials and better use of critical appraisal techniques to evaluate and apply research findings. In addition to more rigorous primary studies, an increasing number of high-quality systematic reviews and evidence-based clinical practice guidelines for low back pain are also available. Although some research gaps and methodologic shortcomings persist, the richer evidence base has greatly improved our understanding of what does and does not work for low back pain. Despite these advances, the best available evidence often does not inform everyday clinical decisions for low back pain. Nonetheless, there is widespread agreement that adherence to evidence-based practice will help improve low back pain patient outcomes and reduce arbitrary variations in care. This article reviews basic principles of evidence-based medicine, discusses evidence-based medicine in the context of low back pain management, and summarizes some useful evidence-based medicine resources.