Objective: To investigate the clinical course of, and prognostic factors for, work-participation in patients with chronic non-specific low back pain. Methods: A total of 1,608 patients with chronic non-specific low back pain received a multidisciplinary therapy and were evaluated at baseline and 2-, 5- and 12-month follow-ups. Recovery was defined as absolute recovery if the patient worked 90% of his contract hours at follow-up. Potential factors were identified using multivariable logistic regression analysis. Results: Patients reported a mean increase in work-participation from 38% at baseline to 82% after 12 months. Prognostic factors for >= 90% work-participation at 5 months were being married (odds ratio (OR) 1.72(95% confidence interval (95% Cl) 1.12-2.65)), male (OR 1.99 (95% CI 1.24-3.20)), a higher score on disability (OR 1.00(95% CI 0.997-1.02)) and physical component scale (Short-Form 36 (SF-36)) (OR 1.05 (95% CI 1.02-1.07)), previous rehabilitation (OR 1.85 (95% CI 1.14-2.98)), not receiving sickness benefits (OR 0.52(95% CI 0.24-1.10)) and more work-participation (OR 4.86 (95% CI 2.35-10.04)). More work-participation (OR 5.22 (95% CI 3.47-7.85)) and male sex (OR 1.79 (95% CI 1.25-2.55)) were also prognostic factors at 12-month follow-up. Conclusion: At 12 months 52% of patients reported >= 90% work-participation. The strongest prognostic factor was more work-participation at baseline for the recovery of chronic non-specific low back pain.