The majority of previous clinical studies have indicated that repetitive transcranial magnetic stimulation (rTMS) may have antidepressant effects. Herein, we investigated the longitudinal, long-term antidepressant efficacy of daily left prefrontal cortex (PFC) rTMS for a 1-week period. Nineteen patients were randomly assigned to two treatment groups at 90% of individual motor threshold (MT): Twelve received active repetitive transcranial magnetic stimulation and seven received sham treatment. Each patient underwent five sessions of twenty 2-s trains of 20 Hz rTMS with 800 stimuli/day. The Beck Depression Inventory and the Hamilton Depression Rating Scale were used to assess severity of depression at 1, 4 and 12 weeks post-therapy. A significant reduction of baseline depression scores was observed after 1 week of active treatment that lasted for 1 month, indicating improvement of depressive symptoms. No significant effects were observed in patients receiving sham treatment. The results of this controlled study are in agreement with the findings of previous studies suggesting that daily left PFC rTMS has an antidepressant effect.