Study Design. Systematic review and best evidence synthesis.Objectives. To describe the prevalence and incidence of neck pain and disability in workers; to identify risk factors for neck pain in workers; to propose an etiological diagram; and to make recommendations for future research.Summary of Background Data. Previous reviews of the etiology of neck pain in workers relied on cross-sectional evidence. Recently published cohorts and randomized trials warrant a re-analysis of this body of research.Methods. We systematically searched Medline for literature published from 1980 -2006. Retrieved articles were reviewed for relevance. Relevant articles were critically appraised. Articles judged to have adequate internal validity were included in our best evidence synthesis.Results. One hundred and nine papers on the burden and determinants of neck pain in workers were scientifically admissible. The annual prevalence of neck pain varied from 27.1% in Norway to 47.8% in Qué bec, Canada. Each year, between 11% and 14.1% of workers were limited in their activities because of neck pain. Risk factors associated with neck pain in workers include age, previous musculoskeletal pain, high quantitative job demands, low social support at work, job insecurity, low physical capacity, poor computer workstation design and work posture, sedentary work position, repetitive work and precision work. We found preliminary evidence that gender, occupation, headaches, emotional problems, smoking, poor job satisfaction, awkward work postures, poor physical work environment, and workers' ethnicity may be associated with neck pain. There is evidence that interventions aimed at modifying workstations and worker posture are not effective in reducing the incidence of neck pain in workers.Conclusion. Neck disorders are a significant source of pain and activity limitations in workers. Most neck pain results from complex relationships between individual and workplace risk factors. No prevention strategies have been shown to reduce the incidence of neck pain in workers.