Family-oriented approaches and consequent conjoint marital sessions have been widely accepted as ingredients of comprehensive treatment and rehabilitation of chronic pain patients. However, no controlled trials have been conducted to confirm the effectiveness of couple therapy in these patients. We examined 63 chronic low back pain (CLBP) patients identified in primary health care centres. They were randomly allocated to a couple therapy group (n = 33) and to a control group without couple therapy (n = 30). The therapy consisted of five monthly sessions and was attended by two family therapists. All patients attended an initial examination and a 12-month follow-up examination. Effects on self-reported pain, disability, and some clinical measures, as well as on the use of medical services were evaluated. The study groups did not differ significantly in any of the outcome measures. Hence, we conclude that couple therapy has no significant effect on disability in CLBP patients.