Transcranial static magnetic stimulation (tSMS) modulates the excitability of the brain, independently of the polarity of the applied magnetic field. The mechanisms involved in this non-invasive brain stimulation technique are not fully understood. Limited studies have shown that the action of the tSMS is primarily at the synapse. It has also been proposed that these magnetic fields alter the function of cell membrane ion channels. We present here clear evidences that incriminate the nitric oxide (NO) molecule as a key factor that explains the effects of tSMS in neural systems.