This systematic review was undertaken to assess the effectiveness of 904nm low level laser therapy (LT) in musculoskeletal disorders. In order to retrieve randomized trials, computer-aided searches of databases and of bibliographic indexes were performed. Furthermore, congress reports, reviews and handbooks were all checked for relevant citations. Subsequently, all retrieved studies were scored on methodological quality. This review found 25 studies that investigated the effects of 904nm LT versus placebo or any other intervention, in subjects with a condition for which LT was thought a feasible intervention. Of these, 21 fulfilled the entry criteria for this review, and were assessed in a blinded manner on methodological criteria. Overall, study quality ranged from ‘poor’ to ‘reasonable’. In a classification of the material into diseases studied, no clear evidence was found for the effectiveness of LT, except perhaps for knee problems and myofascial pain. It is concluded that 904nm LTdoes not seem to be effective in the treatment of musculoskeletal disorders, but that further and improved research is needed to shed more light on its effectiveness.