Isolated spinal accessory nerve palsy after coronary artery bypass graft (CABG) surgery is a rare complication. We report a case of a 52-yr-old male patient who presented with right shoulder weakness, drooping of shoulder, and weakness of forward elevation after CABG. A program of neuromuscular electrical stimulation and exercises was started after the diagnosis of right isolated spinal accessory nerve palsy by physical examination and electromyographic study. Involved muscle function recovered after 6 mos of physical therapy and rehabilitation. This case report suggests that isolated spinal accessory nerve palsy should be considered in cases of shoulder pain or weakness after CABG, and conservative treatment is recommended if palsy develops.