Objective: To examine the effect of adding aerobic exercise (AE) to neck-specific exercise treatment for patients with neck pain (NP) to reduce pain and disability. Design: A prospective multicentre randomized controlled trial. Setting: Physiotherapy outpatient clinics. Subjects: Patients with nonspecific NP. Intervention: Patients with NP were randomly assigned to six weeks of neck-specific exercise with and without the addition of AE. Measures: Patients were classified as having a successful or non-successful outcome according to the Global Rating of Change (GROC). Outcome measures included Visual Analogue Scale (VAS), Neck Disability Index (NDI), Fear Avoidance Beliefs Questionnaire (FABQ) and cervicogenic headache. Assessments were performed at six-week, and three- and six-month follow-ups. Results: A total of 139 participants (mean age: 54.6 ± 10.5 years) were recruited ( n = 69 AE, n = 70 control). According to GROC, 77.4% of the AE group reported a successful outcome at six months vs. 40% in the control group ( P < 0.001). There was a significant reduction in VAS from baseline to six months in the AE vs. control group 6.73 (±1.69) to 1.89 (±1.37) vs. 6.65 (±1.67) to 3.32 (±1.82), respectively ( P  < 0.001). Significant improvements were also obtained for NDI and FABQ from baseline to six weeks in the AE group: NDI from 16.10 (±4.53) to 7.78 (±4.78) vs. 17.01 (±4.84) to 11.09 (±5.64) in the control group ( P = 0.003); FABQ from 33.53 (±9.31) to 20.94 (±841) in the AE vs. 33.45 (±10.20) to 26.83 (±10.79) in the control group ( P < 0.001). The AE group also demonstrated significant reduction in cervicogenic headache from baseline to six months ( P = 0.003). Conclusion: Adding AE to long-term neck-specific exercises is an effective treatment for reducing NP and headache in patients with NP.