The objective of this study is to compare the costs and benefits of a graded activity (GA) intervention to usual care (UC) for sick-listed workers with non-specific low back pain (LBP). The study is a single-blind, randomized controlled trial with 3-year follow-up. A total of 134 (126 men and 8 women) predominantly blue-collar workers, sick-listed due to LBP were recruited and randomly assigned to either GA (N = 67; mean age 39 +/- 9 years) or to UC (N = 67; mean age 37 +/- 8 years). The main outcome measures were the costs of health care utilization during the first follow-up year and the costs of productivity loss during the second and the third follow-up year. At the end of the first follow-up year an average investment for the GA intervention of 475 euros per worker, only 83 euros more than health care utilization costs in UC group, yielded an average savings of at least 999 euros (95% CI: -1,073; 3,115) due to a reduction in productivity loss. The potential cumulative savings were an average of 1,661 euros (95% CI: -4,154; 6,913) per worker over a 3-year follow-up period. It may be concluded that the GA intervention for non-specific LBP is a cost-beneficial return-to-work intervention.