OBJECTIVES: To investigate both clinical effects and costs of acupuncture under general medical practice for patients with chronic low back pain (CLBP) in Korea. METHODS: A multicenter prospective observational study was performed. Outpatients with CLBP who received at least one acupuncture session in a Korean Medicine clinic during the study period were included and followed up for 3 months. All patients received regular acupuncture treatments in accordance with the doctors’ discretion. The clinical effects were measured by condition-specific outcomes and preference-based outcome. In terms of cost analysis, the cumulative resource use for direct medical costs at each research clinic during the study period and direct patient data using the self-reported health care utilization questionnaires were used. RESULTS: A total of 105 patients were finally analyzed. Significant improvements in condition-specific and preference-based measures were observed after acupuncture treatment. An average of approximately $134 per patient was reported for direct medical costs in each clinic for one month (8.5 sessions) and $213 for three months (13.5 sessions). Other medical expenses related to CLBP were reduced during this period.  CONCLUSIONS: Acupuncture to manage CLBP in general clinical practice in Korea, inexpensively improved pain, functional disability, and quality of life. The study results are meaningful and consistent with the results of previous randomized controlled trials performed in other European countries. A large-scale prospective cohort or registry based on practice may be helpful to strengthen the evidence of the cost-effectiveness of acupuncture.