The purpose of this Dutch prospective population-based study was to identify prognostic factors for return-to-work of employees with 3-4 months sick leave due to low back pain (LBP). A cohort of 328 employees was formed and baseline data were collected. One year after the first day of the sick leave, 91% of the original cohort participated in a second interview (n=298). During the baseline measurement, information was collected about health status, history of LBP, occupational variables, job characteristics and social economic variables. At the second interview, 66% of the employees had returned to work (n=198). Return-to-work was independently predicted by having a better general health status (OR 1.53; 95% CI 1.30-1.80), having better job satisfaction (OR 1.26; 95% CI 1.11-1. 44), being a bread winner (OR 2.46; 95% CI 1.37-4.40), having a lower age (OR 0.70; 95% CI 0.52-0.93) and reporting less pain (OR 0. 85; 95% CI 0.73-0.99) all measured at cohort entry. This study shows that psycho-social aspects of health and work in combination with economic aspects have a significantly larger impact on return-to-work when compared to relatively more physical aspects of disability and physical requirements of the job. This suggests that interventions aimed at return-to-work of employees sicklisted with LBP should predominantly be focused on these psycho-social aspects such as health behavior and job satisfaction, and on the (lack of) economic incentives for return-to-work.