One shortcoming of clinical practice guidelines is that generic, one-for-all guideline recommendations do not account for differences among patients' views about the desirability (or undesirability) of specific health outcomes, such as low back pain. Because differences in patients' preferences may lead to differences in the preferred therapy, a clinical practice guideline that does not consider patients' preferences may provide recommendations that are not optimal. Recently developed methodologic approaches enable guideline developers to assess the role of patients' preferences in clinical decisions and guideline recommendations, and to develop preference-based guidelines. Preference-based guidelines are more likely to meet criteria for high-quality guidelines than are guidelines developed without consideration of the role of patients' preferences. Guideline developers should identify decisions in which patient preferences are important and note these decisions clearly in the written guideline; indicate the specific health states for which preferences are important; and, if possible, provide recommendations about options for preference assessment. These options range from informal discussions with patients to computer-based utility assessments. Patients' preferences are an important factor in clinical decisions regarding management of low-back pain, particularly in decisions about surgical management and symptom control. Although further research is needed to define the role of techniques for assessing patients' preferences in routine clinical practice, guideline developers can determine when patients' preferences should play a prominent role in guideline recommendations.