We report a rare complication in a patient with Parkinson's disease who underwent deep brain stimulation(DBS)surgery. The patient was a 60-year-old woman who presented with frontal lobe signs, including ataxic gait and memory disturbance, that were caused by the unexpected migration of a burr hole cap into the brain three to four months after surgery. The patient had no incidence of a head injury prior to development of symptoms. The patient underwent surgery to extract the migrated cap from the frontal lobe, and her symptoms improved several months after the operation. The cap serves to fix the DBS lead to the skull using an adjunctive burr hole ring. It was intraoperatively confirmed that only the cap detached from the ring, and no cap or ring defects were detected in a postoperative quality check by the manufacturer. We have previously utilized a burr hole ring and cap, which are packaged along with the DBS electrode, when employing the product made by Medtronic Inc. No previous report has described the cap packed in the official DBS kit to have migrated into the intracranial space. It seems unlikely that the cap migration into the intracranial space would occur without the cap and/or ring breaking through either traumatic injury or from manufacturing defects. It is important to consider the migration of a burr hole cap into the intracranial space in the absence of head injury as a possible device complication after DBS surgery.