Chronic pain is usually defined as pain of more than three months duration. The prevalence of chronic pain among the general population in Sweden is 18%. Compared with the general population, these patients report lower life satisfaction, decreased activity in daily life and higher levels of depression with decreased work ability, and increased sick leave. Research indicates that multimodal rehabilitation (MMR) programmes, including cognitive behavioural approaches for patients disabled by chronic pain, are effective for return to work. The primary aim of this thesis was to assess outcomes by a long-term follow-up of patients with chronic musculoskeletal pain. Furthermore, the aim was to evaluate two different rehabilitation strategies regarding impact on pain intensity, activity, depression, life satisfactions, and sick leave. Two groups, comprising 255 (between the years 1999-2002) and 296 (between 2007-2008) patients respectively, from the Pain Rehabilitation Clinic at Umeå University Hospital, Sweden, were all assessed by interdisciplinary teams. They completed questionnaires regarding pain intensity, disability, life satisfaction, anxiety and depression, and sick leave, before intervention, immediately after intervention (only the first group; n=255), and at one-year follow-up, after participating in a MMR programme in a specialist clinic, or after receiving a rehabilitation plan (RP) with follow-up in primary care. Allocation to either of the two groups was based on the initial interdisciplinary team assessment. Furthermore, a five-year follow-up of 158 patients with whiplash injury was conducted. Pain intensity decreased and life satisfaction increased significantly regarding somatic health in both groups, at follow-up. In addition, depression improved and disability decreased to a higher extent after participating in the MMR programme as compared to RP and subsequent follow-up in primary care. Patients’ positive beliefs about recovery, and positive expectations about work correlated with favourable rehabilitation outcomes. Sick leave at one year follow-up decreased in both groups. Regarding whiplash injury, patients who reported moderate or severe disability also reported significantly higher pain intensity, depression and post-traumatic stress scores and lower perception of general health compared with patients who reported mild or no disability. In conclusion, MMR programmes seem to be beneficial by decreasing pain intensity, depression, disability and sick leave among patients with chronic musculoskeletal pain. Furthermore, patients’ positive beliefs correlate with more favourable long-term outcomes. An interdisciplinary team assessment based on a biopsychosocial approach may be of value for selection of rehabilitation strategy.