Study Design. An observational registry-based study. Objective. We investigated the long-term patterns of sick leave among patients undergoing surgery for lumbar disk herniation using two nationwide databases to study the achievement of post-surgery return to work (RTW). Summary of Background Data. The ability to RTW is increasingly recognized as an essential outcome measure for spine surgery. Methods. The study included 13,698 patients aged 18 to 60 on sick leave undergoing surgery for lumbar disk herniation from January 2007 through January 2019. Data from the Norwegian Registry for Spine Surgery (NORspine) and the Norwegian Labour and Welfare Administration (NAV) were linked. Certified sick leave around the time of surgery was assessed. The patients were further categorized according to the length of pre-surgery sick leave, and the rate of sustainable RTW for the different groups was compared using survival analysis. The association between successful surgical outcomes, defined by a 30% improvement in Oswestry Disability Index score, and achievement of sustainable RTW was analyzed using a logistic regression model. Results. Two years after surgery, 76% of the patients had returned to work. Shorter pre-surgery sick leave was associated with a higher proportion and rate of achieved sustainable RTW: Among patients with sick leave of less than 30 days, a total of 99% achieved sustainable RTW (median 46 d); only 40% of patients with longer-lasting work assessment allowance achieved the same goal within two years. Successful surgical outcomes were associated with sustainable RTW for all patient groups, but the impact of surgical success on RTW declined as sick leave extended beyond 180 days. Conclusion. Most patients had returned to work two years after lumbar disk herniation surgery. Shorter pre-surgery sick leave was associated with achieving faster and more sustainable RTW. Successful surgical outcomes had less impact on patients with extended sick leave. Level of Evidence III