Work-related upper extremity disorders are a major cause for complaints and disability in worker populations. They may consist of a range of symptoms in the upper extremity, either clearly localised or more widespread, and are usually preceded or affected by exposure to physical activities and/or postures at work. In order to develop effective management strategies, both from a prevention and treatment perspective, more knowledge is needed with regard to the nature, pathophysiological mechanisms and risk factors of this group of disorders. This chapter reviews the clinical manifestations, mechanisms and aetiology of work-related upper extremity disorders through an exploration of the literature. We also examine and discuss the evidence for the effectiveness of several preventative and therapeutic interventions.