Study Design.: Economic evaluation from a societal perspective alongside a 12-months randomized-controlled trial. Objective.: To determine the cost-effectiveness of wearing a lumbar support for home care workers with recurrent low back pain (LBP) (secondary prevention). Summary of Background Data.: LBP is a large medical and economical burden. Evidence on the secondary preventive use of lumbar supports is sparse. Methods.: A total of 360 home care workers with a self-reported history of LBP were randomly assigned to usual care or usual care plus wearing a lumbar support on working days with LBP, during a 1-year period. Primary clinical outcome measures were the average number of self-reported days with LBP, number of calendar days sick leave in general, and quality of life. Direct and indirect costs were measured by means of cost diaries. Differences in mean costs between groups, cost-effectiveness, and cost-utility ratios were evaluated, and cost-effectiveness planes and acceptability curves presented by applying nonparametric bootstrapping techniques. Results.: During the intervention period, the home care workers using a lumbar support in addition to usual care reported on average 54 fewer days with LBP (95% confidence interval [CI], -85 to -29). The estimated mean difference in sick leave was not statistically significant (-5.0 days per year in favor of the lumbar support group; 95% CI, -21.1 to 6.8). There was no statistically significant difference in quality of life. Direct costs were &OV0556;235 (US$ 266) lower in the lumbar support group (95% CI, -386 to -79). Indirect costs were &OV0556;255 (US$ 288) lower, but this was not statistically significant (95% CI, -879 to 299). Conclusion.: Lumbar support seems to be a cost-effective addition to usual care for home care workers with recurrent LBP. For estimating the LBP-related indirect costs, it would be more precise when an objective measure for LBP-related sick leave would have been available. There is a need for more evidence to confirm these findings, also in other working populations. © 2010, Lippincott Williams & Wilkins.