Cognitive behavioural therapy (CBT) improves pain outcomes in patients with fibromyalgia, but the underlying neural mechanisms are unclear. New data show that pain-associated catastrophizing correlated with resting-state functional MRI (fMRI) activity indicating connectivity between pain-processing brain regions in 16 high-catastrophizing patients with fibromyalgia, who were then randomly allocated to receive CBT or education-based treatment for 4 weeks. Catastrophizing was reduced to a significantly greater degree in the CBT group than in the control group post-treatment and at 6-month follow-up. Notably, the CBT-associated clinical improvement correlated with post-treatment reduction of pain-associated fMRI activity.