Study Design. A cross-sectional study of physicians and physiotherapists in primary care. Objectives. To survey how familiar clinicians were with evidence-based guidelines for back pain and their opinion about their clinical usefulness and to compare self-reported practice behavior with the guidelines. Summary of Background Data. Guidelines, based on empirical evidence, are meant to ensure that patients get the most effective treatment. These evidence-based guidelines should steer clinical praxis, but clinicians may not read, let alone heed, them. Methods. Using a questionnaire, the authors surveyed all physicians and physiotherapists in primary health care in Orebro County, Sweden (N = 235). Results. Forty-two percent of the physicians and 37% of the physiotherapists were unfamiliar with the content of the guidelines, and 40% of the physicians and 25% of the physiotherapists were unfamiliar with the concept of "red flags." Less than half of the clinicians, 47%, were familiar both with the content of the guidelines and the concept of red flags. Their opinion about the guidelines showed that 54% of the physicians and 56% of the physiotherapists agreed that the guidelines were useful in clinical praxis. Concerning the self-reported practice behavior, the majority indicated that they followed the key points in the guidelines. Conclusions. A relatively large proportion of clinicians were unfamiliar with the content of evidence-based guidelines and/or with the concept of red flags. The process of implementing research into clinical practice is in need of an overhaul, and the impact of guidelines on clinical practice may be questioned.