BACKGROUND: Implantable electrical devices are becoming increasingly common in the patient population presenting for Mohs micrographic surgery. In addition to understanding the potential intraoperative complications with implantable cardioverter-defibrillators and pacemakers, the Mohs surgeon needs to be aware of the relatively new treatment of movement disorders using implanted deep brain stimulators. OBJECTIVE: We present only the second reported case of Mohs surgery in a patient with a deep brain stimulator. In an attempt to help minimize adverse events during a procedure, we review the more commonly encountered electrical devices as well as the newer deep brain stimulators. We provide guidelines for the avoidance of electromagnetic interference during an electrosurgical procedure. METHODS: This 76-year-old patient with Parkinson's disease and an implanted deep brain stimulator underwent Mohs surgery for excision of a squamous cell carcinoma on the ear. In an attempt to minimize electromagnetic interference with his implanted device, hemostasis was obtained with the aid of a battery-operated heat-generating handheld electrocautery device. RESULTS: The patient tolerated the procedure well without complications or reports of discomfort. CONCLUSION: Patients with implanted electrical devices are subject to electromagnetic interference during an electrosurgical procedure. Care must be taken in this expanding patient population during a Mohs surgical procedure.