Purpose The aim of this study was to assess short and long-term effectiveness of brief coping-focused psychotherapy (Brief-PsT) compared with short-term psychotherapy (Short-PsT) on work-participation (WP) and mental health. Both treatments were preceded by group education. Methods All participants were on, or at risk of, sick leave due to common mental complaints. Patients were selected for inclusion in this study based on levels of self-reported symptoms (‘some’ or ‘seriously affected’) of anxiety and depression. They were randomized to Brief-PsT (n = 141) or Short-PsT with a more extended focus (n = 143). Primary outcome was the transition of WP-state from baseline to 3 months follow-up. In addition, WP at 12 and 24 months follow-up were assessed. The secondary outcome, clinical recovery rate (CR-rate) was obtained from the Beck Depression and Beck Anxiety Inventories, at 2-year follow-up. In addition, self-reported mental health symptom severity, self-efficacy, subjective health complaints and life satisfaction were assessed. Results At 3 months follow-up, the increase in WP was significantly greater in Brief-PsT than in Short-PsT (p = 0.039). At 3 months, 60% in Brief-PsT and 51% in Short-PsT was at work, partial or full. Thereafter, these differences diminished, 84% and 80% were at work at 2-year follow up. The 2-year follow-up of the secondary outcome measurements was completed by 53% in Brief-PsT and 57% in Short PsT. CR-rate was significantly greater in Brief-PsT compared with the Short-PsT (69% vs. 51%, p = 0.024). Furthermore, there was a greater reduction in the number of subjective health complaints in Brief-PsT (4.0 vs. 1.9 p = 0.012). All other measurements favoured Brief-PsT as well, but did not reach statistical significance. Conclusions Brief coping-focused psychotherapy added to group education for persons with depression or anxiety complaints seemed more effective in enhancing early work participation compared with additional short-term psychotherapy of standard duration with more extended focus. Clinical recovery rate and decline of comorbid subjective health complaints at 2-year follow-up were also in favour of the brief coping-focused program.