Several treatment principles for the reduction of chronic low back pain associated disability have been postulated. To examine whether a combination of a physical training and operant-behavioral graded activity with problem solving training is cost-effective compared to either alone one year post-treatment, a full economic analysis alongside a randomized controlled trial was conducted. in total 172 patients with chronic disabling non-specific low back pain referred for rehabilitation treatment, were randomized to 10 weeks of aerobic training and muscle strengthening of back extensors (active physical treatment; APT), 10 weeks of gradual assumption of patient relevant activities based on operant-behavioral principles and problem solving training (graded activity Plus problem solving training; GAP), or APT combined with GAP (combination treatment; CT). Total costs, existing of direct health and non-health costs and indirect costs due to absence of paid work were Calculated by using cost diaries and treatment attendance lists. The Roland Disability Questionnaire was used to calculate the cost-effectiveness to reduce disability and the gain in quality adjusted life year (QALY) by using the EuroQol-5D. APT, followed by CT showed, although not significant, higher total costs than GAP. Reduction of disability and gain in QALY did not differ significantly between CT and the single treatment modalities. Based on the incremental cost effectiveness ratios (ICERs) and cost-effectiveness acceptability curves CT is not cost-effective at all. However, GAP is cost-effective regarding the reduction of disability and gain in QALY, and to a lesser degree APT is more cost-effective than CT in reducing disability.