Work-related musculoskeletal disorders of the upper limb (WRMSDs-UL) account for over two-thirds of all occupational disorders recognized in France. This broad term encompasses a vast array of disorders whose development is facilitated by environmental factors present at the workplace. Numerous epidemiological studies have established the key role of occupational activities in the genesis of WRMSDs-UL. This role is mediated by biomechanical factors (repetitive motion, strenuous effort, extreme joint postures) and/or psychosocial factors. Biological plausibility supports the epidemiological data. The high incidence of WRMSDs-UL indicates a need for greater emphasis on prevention.