Background: Back pain is a common patients' complaint, and its etiology is important because of different potential treatment approaches (based on causes). For a better diagnosis, magnetic resonance imaging (MRI) is widely used in clinical settings that may result in inappropriate requests. This study aims to evaluate the appropriateness of the lumbosacral MRI requests in patients with back pain in two public/referral and private imaging centers in Tehran. Methods: In this cross-sectional study, 279 patients from both centers were recruited in 2014. A checklist was developed based on the internationally recognized clinical guidelines (NICE, and AHRQ) for determining the indications. An expert panel of related specialties finalized them. Patients' demographic and some anthropometric measures, as well as MRI reports, were collected. Results: The mean±SD age of patients was 47.9±14.78 years with a dominance of females (M/F=38.4/61.6). About 77 (n=214) of lumbosacral MRIs were requested in accordance with the guidelines. Indicated MRI requests were significantly higher in the private imaging center (p=0.019, OR=2.087, CI 95: 1.13-3.85). In the private center, 80.6 and in the public center, 70.4 of the MRI requests were in accordance with the guidelines. Conclusion: The proportion of non-indicated MRI requests based on the valid guidelines is about 1/4 of all requests that is compatible with some other studies mostly from developed countries
