The purpose of the present study was to determine exactly the incidence of surgical complications in patients for whom MRI-targeted, microelectrode recording (MER)-guided implantation of deep brain stimulation (DBS) or radiofrequency (RF)-coagulation surgery was performed. Between January, 1998 and September, 2002, a total of 110 stereotactic surgeries for movement disorders (57 RF-coagulations and 53 implantations of DBS) were performed. We investigated the type and number of complications for each of the following surgical targets; globus pallidus, thalamus, and subthalamic nucleus (STN). Twenty-four neurological complications in 22 patients and 16 radiological/instrumental complications in 16 patients were verified among the 110 surgeries. Among the neurological complications, hemiparesis and mental disturbances were observed at a high rate, while intraoperative hemorrhage frequently occurred among the radiological/instrumental complications. The rate of neurological and radiological/instrumental complications for each of the stereotactic targets; the globus pallidus, thalamus, and STN-targeted surgeries, was 32.4%, 16.7%, 18.8% and 16.2%, 20.0%, 12.5%, respectively. The reason for the high rate of intraoperative hemorrhage may be associated with technical problems resulting from the penetration of vessels by needles, as well as the destruction of small vessels due to heat ablation. As for the mental disturbances, visual hallucinations (VH) occurred a high rate, especially during STN-DBS. Peduncular damage and/or L-dopa toxicity due to STN-DBS may have been associated with VH, so the STN-DBS may therefore be thought to change the threshold of stimulus-induced hallucinations. We also found that the procedures for DBS surgery, especially in younger patients, have a lower risk of complication, while, on the other hand, coagulation surgery for elderly patients is accompanied by of high risks, from the standpoint of surgical complications.