Objective To investigate the effects of a group-based cognitive behavioural intervention for patients with persistent low back pain (LBP) and psychological risk factors referred to secondary care. Design A randomised controlled trial. Setting Silkeborg Regional Hospital, Denmark. Subjects A total of 136 participants with chronic LBP and psychological risk factors. Interventions Participants were randomised to the standard care group, including examination by a rheumatologist and/or a physiotherapist, or the intervention group, including standard care plus a multidisciplinary group-based pain management programme. Main measures Patient-reported outcomes were collected at baseline and after 6 and 12 months. The primary outcome was disability (Roland Morris Disability Questionnaire). Secondary outcomes included low back pain intensity, pain catastrophising, health-related quality of life, and sick leave. Results Among 136 participants, 68 (mean age: 41.7 years (SD 11.8)) were randomised to standard care and 68 (mean age: 46.0 years (SD 10.8)) were randomised to the intervention group. Except for age, baseline characteristics were comparable between groups. 12-month follow-up was completed by 92.6% in the intervention group and 80.9% in the standard care group. Both groups achieved significant improvements on disability, with a reduction of −4.8 points (SD 6.1) in the intervention group compared to −3.7 points (SD 5.2), resulting in an insignificant difference between groups. No significant differences were found in the secondary outcomes. Conclusion A group-based pain management programme was no more effective than standard care for patients with persistent LBP and psychological risk factors.