This study examined the contributing effects of hypnosis on a standard cognitive-behaviour therapy (CBT) intervention for treating pain in patients with fibromyalgia. Forty-seven patients with fibromyalgia were randomly assigned to one of three conditions: (1) Pharmacological treatment (standard care control group); (2) CBT group therapy; or (3) CBT group therapy with hypnosis. Outcome measures assessing pain intensity, sensorial and affective quality of pain and total FIQ score were administered before and after treatment. The analyses indicated that patients who received either CBT or CBT plus hypnosis improved more than patients who received only conventional pharmacological treatment; patients who received CBT plus hypnosis showed greater improvement than those who received CBT without hypnosis. The findings are consistent with previous research demonstrating the additive benefits of hypnosis when combined with other effective treatments. Copyright © 2008 British Society of Experimental & Clinical Hypnosis. Published by John Wiley & Sons, Ltd.