Background. In 2002, the Danish Cancer Society opened a rehabilitation centre in which cancer patients were offered a free, six-day, multidimensional residential course. Our previous studies of the effects of this course at one and six months of follow-up showed no positive effect on distress. We investigated long-term effects at 12 months of follow-up and whether subgroups with fewer psychosocial resources received more benefit from the intervention than patients with better resources. Material and methods. In two Danish counties, 507 patients with breast, prostate, colon or rectum cancer diagnosed within the past two years who had completed primary treatment were randomised to a six-day, multidimensional residential rehabilitation course or to standard care. Of these, 208 patients received the allocated intervention and 244 received the allocated control condition and were included in the analyses. Patients in both groups completed questionnaires at baseline and at one, six and 12 months of follow-up, including the 'Profile of Mood States short form', the 'General Self-efficacy' scale and a question on emotional support. At 12 months of follow-up, 179 participants in the intervention group and 195 in the control group provided data. Results. No effect of the intervention was found on distress at 12 months of follow-up, even in subgroups with fewer psychosocial resources at baseline, i.e. greater baseline distress, poorer self-efficacy and less emotional support. Conclusion. Multidimensional rehabilitation programmes may not be effective in the treatment of distress. During the past few decades, studies of psychotherapy or psycho-education in cancer patients have shown small to moderate effects. More focused rehabilitation programmes may be more effective.