Objective: To evaluate the cost effectiveness of physiotherapy, manual therapy, and care by a general practitioner for patients with neck pain. Design: Economic evaluation alongside a randomized controlled trial. Setting: Primary care. Participants: A total of 183 patients with neck pain for at least two weeks recruited by 42 general practitioners and randomly allocated to manual therapy (n=60, spinal mobilization), physiotherapy (n=59, mainly exercise), or general practitioner care (n=64, counseling, education, and drugs). Main outcome measures: Clinical outcomes were perceived: recovery, intensity of pain, functional disability, and quality of life. Direct and indirect costs were measured by means of cost diaries that were kept by patients for one year. Differences in mean costs between groups, cost effectiveness, and cost utility ratios were evaluated by applying non-parametric bootstrapping techniques. Results: The manual therapy group showed a faster improvement than the physiotherapy group and the general practitioner care group up to 26 weeks, but differences were negligible by follow-up at 52 weeks. The total costs of manual therapy (447 EUR) were around one third of the costs of physiotherapy (1297 EUR) and general practitioner care (1379 EUR). These differences were significant:p<0.01 for manual therapy vs. physiotherapy and manual therapy vs. general practitioner care, and p=0.55 for general practitioner care vs. physiotherapy. The cost effectiveness ratios and the cost utility ratios showed that manual therapy was less costly and more effective than physiotherapy or general practitioner care. Conclusions: Manual therapy (spinal mobilization) is more effective and less costly for treating neck pain than physiotherapy or care by a general practitioner.