PURPOSE To assess the prevalence of appropriate imaging among emergency department (ED) patients with low back pain. METHODS Our level-1 ED records were retrospectively searched for patients with a chief compliant of "low back pain" from January to April 2013. Of 624 patients, 100 were randomly selected and analyzed for their demographics, presentation, imaging, treatment, and outcomes. The study indication for imaging was compared with the ACR Appropriateness Criteria, and the indication was deemed appropriate if it received a rating of ≥5. RESULTS The mean age of the study population was 48 years (50% women, 50% men). The majority presented with acute or acute on chronic low back pain (94 patients), and half had a precipitating event (50 patients). A total of 28 (28%) patients underwent imaging in the ED; 24 (24%) had outpatient imaging; 54 (54%) had neither ED nor outpatient imaging. In all, 96% (27 of 28) of patients imaged in the ED, and 96% (23 of 24) imaged as outpatients, were appropriately imaged. Of patients who did not undergo imaging, 96% (52 of 54) were appropriately not imaged. A total of 76 patients (76%) had follow-up after discharge: of these, 42 (55%) had resolution or return of pain to baseline with conservative management; 18 (24%) had improvement with intervention (epidural steroid injection or kyphoplasty); 8 (10%) improved with surgery; and 8 had persistent pain (11%). CONCLUSIONS The majority of patients presenting to the ED with low back pain did not undergo imaging. The vast majority of those who underwent imaging were appropriately imaged, based on the ACR Appropriateness Criteria.