OBJECTIVES: To identify risk factors for musculoskeletal symptoms in aviation maintenance technicians in order to provide basic information for intervention programs to prevent and manage musculoskeletal symptoms for these technicians. METHODS: Between October 18 and 25, 2004, 286 aviation maintenance technicians answered a self-administered questionnaire, which included general characteristics, Karasek's Job Content Questionnaire for psychosocial characteristics, and work-related characteristics. The musculoskeletal symptoms were evaluated using the National Institute of Occupational Safety and Health (NIOSH) surveillance criteria. Statistical analysis included means and standard deviation, x2-test, t-test, and logistic regression. RESULTS: A quarter (25.8%) of the workers reported musculoskeletal symptoms in more than one body region. The prevalence of symptoms was 12.9% in the lower back, 10.2% in the shoulders, 9.4% in the legs/foots, 9% in the neck, 5.9% in the hands/wrists/fingers, and 2.7% in the arms/elbows. General characteristics were not found to influence musculoskeletal symptoms, except that workers practicing regular exercise reported fewer lower back symptoms (p=.038). Low social support (p=.001), and low supervisory support (p=.000) were significant factors for increased musculoskeletal symptoms whereas decisions latitude, psychological job demands, and co-worker support were not found to have significant associations, with the exception of low decision latitude which was significantly associated with increased legs/foots symptoms (p=.034). More than two thirds (69.6%) of the workers whose perceived physical load was very high complained of symptoms. This rate was eight times higher than for workers whose perceived load was very low (p=.000). The workers highly exposed to both physical and psychosocial risk factors were more likely to report musculoskeletal symptoms than workers highly exposed to only one of these factors (p=.000). The odds ratios for very high-perceived physical load (OR 13.9) and low supervisory support (OR 2.9) were clearly increased. CONCLUSIONS: The results of this study suggest that consideration for perceived physical load and psychosocial characteristics as important determinants is necessary to prevent musculoskeletal symptoms in aviation maintenance technicians. To develop effective intervention programs to prevent musculoskeletal symptoms, a comprehensive and systematic approach should be the basic premise. Such an intervention program should consist of ergonomic, managerial and behavioral interventions to reduce physical load and psychosocial factors.