Former studies have questioned the effectiveness of multidisciplinary rehabilitation for working-age adults with musculoskeletal pain problems. The lack of analysis within subgroups may explain why an effect of treatment of long-term musculoskeletal pain was not documented in former studies. In this article three later studies on long-term musculoskeletal pain patients are presented. The challenge of these studies was to identify subgroups of patients who benefit from different types of treatments. This article present the main findings of a large RCT with up till 54 months of follow-up among 664 persons sicklisted for musculoskeletal pain. It was hypothesised that different categories of patients need different treatment programs in order to get back to work. Patients with different prognoses for return to work were identified by means of a screening instrument, and it was tested whether those with poor prognosis need more extensive multidisciplinary treatment, compared to patients with less psychosocial and physical problems. Also, the effect of different treatment programs among patients with different diagnoses (ICD-9, low back pain and chronic widespread pain) and among men and women was examined. The results of the three studies support the authors' hypothesis that different categories of patients need different treatment programs. A higher percentage of return to work was demonstrated when the right treatment was given to the right patient, and considerable cost effectiveness was demonstrated.