Background: A large number of randomized trials on the use of acupuncture to treat chronic pain have been conducted. However, there is considerable controversy regarding the effectiveness of acupuncture. We designed a randomized trial involving patients with chronic neck pain (CNP) to investigate whether acupuncture is more effective than a placebo in treating CNP. Methods/design: A five-arm, parallel, single-blinded, randomized, sham-controlled trial was designed. Patients with CNP of more than 3 months' duration are being recruited from Guangdong Provincial Hospital of Chinese Medicine (China). Following examination, 175 patients will be randomized into one of five groups (35 patients in each group) as follows: a traditional acupuncture group (group A), a shallow-puncture group (group B), a non-acupoint acupuncture group (group C), a non-acupoint shallow-puncture group (group D) and a sham-puncture group (group E). The interventions will last for 20 min and will be carried out twice a week for 5 weeks. The primary outcome will be evaluated by changes in the Northwick Park Neck Pain Questionnaire (NPQ). Secondary outcomes will be measured by the pain threshold, the Short Form McGill Pain Questionnaire-2 (SF-MPQ-2), the 36-Item Short-Form Health Survey (SF-36) and diary entries. Analysis of the data will be performed at baseline, at the end of the intervention and at 3 months' follow-up. The safety of acupuncture will be evaluated at each treatment period. Discussion: The purpose of this trial is to determine whether traditional acupuncture is more effective for chronic pain relief than sham acupuncture in adults with CNP, and to determine which type of sham acupuncture is the optimal control for clinical trials.