Fibromyalgia syndrome is characterized by widespread pain and muscle tenderness. Several lines of evidence suggest that fibromyalgia may be a disorder affecting pain modulation. Repetitive transcranial magnetic stimulation (rTMS) is a novel, safe and non-invasive technique for stimulating the cerebral cortex, which has recently been reported to induce short term analgesic effects in patients with chronic pain. Our aim was to investigate the analgesic effects of repeated daily sessions of unilateral rTMS in patients with fibromyalgia syndrome. Thirty eight patients were screened and 30 non depressed women with fibromyalgia syndrome were included in a parallel group randomized sham controlled trial of the efficacy of 10 daily repeated sessions of rTMS applied over the motor cortex (stimulation rate 10 Hz, 80% of resting motor threshold). Fifteeen women received the active treatment and 15 had the sham stimulation. The assessment performed at baseline and then 15, 30 and 60 days after treatment, included pain intensity (Brief Pain Inventory) and quality (SF McGill Pain Questionnaire), depression, anxiety (Beck, HAD and HDRS scales) and quality of life. All the patients were followed up to 15 and 30 days, and 26 were assessed at 60 days. In comparison with sham stimulation, active rTMS induced significant relief of pain with a preferential reduction of its affective dimension which lasted up to day 30. Several measures of quality of life (fatigue, sleep) were also significantly improved. The efficacy of rTMS was not related to alteration of mood or anxiety. No major side effects were reported.