Former studies have questioned the quality and effectiveness of multidisciplinary rehabilitation for working-age adults with fibromyalgia and chronic widespread pain (CWP). High-quality trials are needed, and return to work should also be included as an outcome variable. This randomized study evaluated the return-to-work outcome of an extensive and a light multidisciplinary treatment program combining cognitive strategies and exercise versus treatment-as-usual initiated by a general practitioner, for CWP patients. The patients (n=208), on sick leave for 3 months on average, were randomized to the extensive program including group sessions, a light and more individual program, and to treatment-as-usual. The number of days absent from work and full return to work were used as an outcome, and follow-up lasted 54 months after the programs ended. The regression analysis showed that the extensive program was associated with significantly fewer days absent from work among women. For women, the mean effect of extensive treatment versus treatment-as-usual on total number of days absent from work was estimated to -206.95 days. Among men, the light program was associated with significantly more days absent from work compared to treatment-as-usual. Both among men and women, independent of type of treatment, patients with poorer health (poor prognosis) were absent from work more days than patients with good prognosis. In our sample, higher age significantly increased the number of days absent from work, but only for women. The extensive outpatient multidisciplinary treatment program was effective in returning women to work.