Acupuncture is increasingly used in patients with chronic pain, but there is a lack of evidence on the cost-benefit relationship of this treatment strategy. The objective of this study was to assess costs and cost-effectiveness of additional acupuncture treatment in patients with chronic neck pain compared to patients receiving routine care alone. A randomized controlled trial including patients (18 years of age) with chronic neck pain (>6 months) was carried out. We assessed the resource use and health related quality of life (SF-36) at baseline and after 3 months using complete social health insurance funds and standardized questionnaires, respectively. The main outcome parameters were direct and indirect cost differences during the 3 months study period and the incremental cost-effectiveness ratio (ICER) of acupuncture treatment. A total of 3,451 patients (1,753 acupuncture-group, 1,698 control-group) were randomized (31% men, age 53.5+/-12.9 years; 69% women, 49.2+/-12.7 years). Acupuncture treatment was associated with significantly higher costs over the 3 months study duration compared to routine care (925.53+/-1,551.06 euros vs. 648.06+/-1,459.13 euros; mean difference: 277.47 euros [95% CI: 175.71 euros-379.23 euros]). This cost increase was mainly due to costs of acupuncture (361.76+/-90.16 euros). The ICER was 12,469 euros per QALY gained and proved robust in additional sensitivity analyses. Since health insurance databases were used, private medical expenses such as over the counter medication were not included. Beyond the 3 months study duration, acupuncture might be associated with further health economic effects. According to international cost-effectiveness threshold values, acupuncture is a cost-effective treatment strategy in patients with chronic neck pain.