Objectives To investigate the consequences and costs of acupuncture in general medical practice for patients with chronic low back pain (CLBP) in Korea. Methods A multicentre 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 consequences in terms of effects included condition-specific outcomes and preference-based outcome. For 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 healthcare utilisation questionnaires were used. Results A total of 157 patients were eligible to participate and 105 were finally included. Significant improvements in condition-specific and preference-based measures were observed after acupuncture treatment. An average of approximately $146 (£93) per patient was reported for direct medical costs in each clinic for 1 month and $231 (£148) for 3 months. Other medical expenses related to CLBP were reduced during this period. Conclusions The use of 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 trials performed in other European countries but the power of the study is not strong, having major design weaknesses. A large-scale cohort or registry based on practice may be helpful to strengthen the evidence of the cost-effectiveness of acupuncture.