Background: Patient expectations may be associated with outcomes of complementary and alternative medicine (CAM) treatments for chronic pain. However, a psychometrically sound measure of such expectations is needed.Objectives: The purpose of this study was to develop and evaluate a questionnaire to assess individuals' expectations regarding outcomes of CAM treatments for chronic low back pain (CLBP), as well as a short form of the questionnaire.Methods: An 18-item draft questionnaire was developed through literature review, cognitive interviews with individuals with CLBP, CAM practitioners, and expert consultation. Two samples completed the questionnaire: (1) a community sample (n = 141) completed it via an online survey before or soon after starting a CAM treatment for CLBP, and (2) participants (n = 181) in randomized clinical trials evaluating CAM treatments for CLBP or fibromyalgia completed it prior to or shortly after starting treatment. Factor structure, internal consistency, test-retest reliability, and criterion validity were examined.Results: Based on factor analyses, 10 items reflecting expectations (used to create a total score) and three items reflecting hopes (not scored) were selected for the questionnaire. The questionnaire had high internal consistency, moderate test-retest reliability, and moderate correlations with other measures of expectations. A three-item short form also had adequate reliability and validity.Conclusions: The Expectations for Complementary and Alternative Medicine Treatments (EXPECT) questionnaire can be used in research to assess individuals' expectations of treatments for chronic pain. It is recommended that the three hope questions are included (but not scored) to help respondents distinguish between hopes and expectations. The short form may be appropriate for clinical settings and when expectation measurement is not a primary focus.