This exploratory work aims to hypothesize a methodological tool and EEG biomarkers for the effect of repetitive Transcranial Magnetic Stimulation (rTMS) on patients with schizophrenia and auditory and verbal hallucinations (AVH). Ten patients diagnosed with schizophrenia and pharmacological persistent AVH were divided into two groups: the first group (TG) received 1Hz frequency rTMS treatment during 10 daily sessions (900 pulses/session) over the left T3-P3 International 10-20 location. The second group (CG) received rTMS treatment over the Cz (vertex) EEG location. Data from the patients were acquired before the rTMS treatment (T1) and 10 days after the treatment (T2), and they were compared with the results obtained from a third group of healthy subjects (HS), who did not receive rTMS treatment.