Musculoskeletal disorders account for one third of the long-term absenteeism in Denmark and the number of individuals sick listed for more than four weeks is increasing. Compared to other diagnoses, patients with musculoskeletal diseases, including low back pain, are less likely to return to work after a period of sick leave. It seems that a multidisciplinary intervention, including cooperation between the health sector, the social sector and in the work place, has a positive effect on days off work due to musculoskeletal disorders and particularly low back pain. It is a challenge to coordinate this type of intervention, and the implementation of a return-to-work (RTW)-coordinator is suggested as an effective strategy in this process. The purpose of this paper is to describe the study protocol and present a new type of intervention, where the physiotherapist both has the role as RTW-coordinator and treating the patient.