This is a cross-sectional and prospective study to examine the correlation between the Northwick Park Neck Pain Questionnaire and the Medical Outcomes 36-Item Short-Form Health Survey on patients with neck pain in the course of physiotherapy. A total of 359 consecutive adult patients with neck pain, from three physiotherapy outpatient departments, who completed the Northwick Park Neck Pain Questionnaire and Medical Outcomes 36-Item Short-Form Health Survey, were observed and measured at different intervals - at the beginning of physiotherapy, at week 3, week 6 and upon discharge from physiotherapy. The results showed that both the Northwick Park Neck Pain Questionnaire and the Medical Outcomes 36-Item Short-Form Health Survey were able to differentiate patients with neck pain in health and diseased states. The Spearman's correlation coefficients between the Northwick Park Neck Pain Questionnaire and the 36-Item Short-Form Health Survey physical and mental component summary scores at entry of physiotherapy were -0.64 with the physical component summary score and -0.44 with the mental component summary score, and, at discharge from physiotherapy, were -0.75 with the physical component summary score and -0.46 with the mental component summary score. The Northwick Park Neck Pain Questionnaire has psychometric properties with both physical and mental dimensions of measurement of pain in patients with neck pain.