A higher-than-expected frequency of suicide has been reported among patients undergoing subthalamic nucleus deep brain stimulation (STN DBS) for advanced Parkinson's disease (PD). We conducted a retrospective survey of 200 patients with PD who underwent STN DBS. Two patients (1%) committed suicide and four (2%) attempted suicide, despite clear motor improvements. Suicidal patients did not differ from non suicidal patients with respect to age, disease duration, or pre-operative depressive and cognitive status. Suicidal behavior was associated with post-operative depression and/or altered impulse regulation. Suicidal behavior is a potential hazard of STN DBS, calling for careful preoperative assessment and close post-operative psychiatric and behavioral follow-up.