Objective. To investigate the prevalence and to identify causes of musculoskeletal pain (MSP) among reindeer herding Sami, and to evaluate the impact on the MSP symptoms elicited by an intervention-pre- vention programme (lP programme). Study Design. A prospective cohort study in which alterations in MSP symptoms were documented over a two-year period. Methods. Data were collected from 51 rein- deer herders (26 men, 25 w omen) before and af ter a two-year lP programme. Information on MSP cha- racteristics (affected body regions, pain duration and pain intensity) and exposure to a number of phy- sical and psychosocial risk factors were collected as part of comprehensive health examinations. Cli- nical examinations and interviews complemented self-reported data collected through questionnaires. Results. MSP symptoms were prevalent, both among w omen and men. High exposure to physical risk factors, to a large extent related to extensive use of snowmobiles and motorcycles, was the main cau- se of MSP among men, while psychosocial risk factors were suggested to be more important among wo- men. About one-third of the reindeer herders reported fewer MSP symptoms as a resull of the lP programme. Conclusions. This pilot study suggests that it is possible to reduce the number and the se- verity of the MSP symptoms among reindeer herders by implementing suitably tailored intervention- prevention measures.