OBJECTIVE: Fibromyalgia syndrome (FMS) is a condition of chronic widespread pain that is difficult to control and is associated with strains in physician-patient interaction. Shared decision making (SDM) can be a potential solution to improve interaction. We evaluated the effects of an SDM intervention, including an SDM communication training program for physicians, in a randomized controlled trial with FMS patients. The main objective was to assess whether SDM improves the quality of physician-patient interaction from patients' perspective. METHODS: Patients were randomized to either an SDM group or an information-only group. The SDM group was treated by physicians trained in SDM communication and had access to a computer-based information package; the information-only group received only the information package and was treated by standard physicians. All patients were offered the same evidence-based treatment options for FMS. Patients were assessed with questionnaires on physician-patient interaction (main outcome criteria) and decisional processes. Physicians filled out a questionnaire on interaction difficulties. Assessment took place immediately after the initial consultation. RESULTS: Data from 85 FMS patients (44 in the SDM group and 41 in the information-only group) were analyzed. The mean age was 49.9 years (S.D.=10.2), and 91.8% of patients were female. The quality of physician-patient interaction was significantly higher in the SDM group than in the information-only group (P<.001). We found no differences in secondary outcome measures. CONCLUSIONS: SDM with FMS patients might be a possible means to achieve a positive quality of physician-patient interaction. A specific SDM communication training program teaches physicians to perform SDM and reduces frustration in patients.