Background: According to a recent review by Huppe and Raspe effects of multidisciplinary treatment programs for patients with chronic low back pain in Germany seem to be rather weak and not to have persisting effects [3]. Factors which could counteract possible benefits of treatment are, among others, psychic and job-related stresses and strains persisting after treatment. A multidisciplinary, in-patient treatment program for patients with chronic low back pain, therefore, was amended by multidisciplinary diagnosis and assignment and measures to support vocational solutions. Method: To evaluate the effects of the multidisciplinary program in comparison to a control group with the usual care, a prospective longitudinal study was conducted. 307 patients were assigned to the multidisciplinary in-patient treatment program, whereas 176 patients with comparable complaints had the standard rehabilitation program. Besides the full sample, we analyzed a subgroup of patients with chronic low back pain. Results: We found positive moderate and strong effects in the intervention group concerning function, pain, psychic strains as well as the number of sick days and return to work rates 10 months after discharge. Effects in the intervention group exceeded the effects achieved in the control group. Beside the full sample, we analyzed a subgroup of patients with chronic low back pain, who received an intense activating group treatment. Also in this subgroup we found moderate and strong effects of treatment superior to those in the control group for function, psychic strains and sick days. Conclusion: We attribute these persisting and superior effects in the treatment group to an efficient treatment of occupational and psychic problems as well as to more homogeneous treatment groups attained by a multidisciplinary diagnosis and team-based assignment. They also show the significance of in-patient-treatment which is effective, when - based on multidisciplinary diagnosis - differential treatment groups can be formed.