The aim of this study is to assess the efficacy of repetitive transcranial magnetic stimulation (rTMS) as an add-on therapy in the treatment of manic bipolar patients. Eight patients were enrolled in an open trial. They received fast rTMS (five trains of 15 s, 80% of the motor threshold, 10 Hz) over the right dorsolateral prefrontal cortex (DLPFC). They were evaluated using the Mania Assessment Scale (MAS) and the Clinical Global Impression (CGI) at baseline and at day 14. All patients were taking medication during the treatment trial. There was a significant improvement of manic symptoms at the end of the trial. No side effects were reported. The results show a significant improvement of mania when patients are treated with fast rTMS over the right DLPFC. However, these results have to be interpreted with caution since they derive from an open case series and all the subjects were taking psychotropic medication during rTMS treatment. Double-blind controlled studies with a sham comparison condition should be conducted to investigate the efficiency of this treatment in manic bipolar disorders.