Although iatrogenic injury to the spinal accessory nerve in the posterior cervical triangle is a well-described phenomenon, diagnosis can prove difficult and is often incorrect or delayed. We describe a series of six men and three women (mean age 40 years; range, 20 to 52 years) with iatrogenic spinal accessory nerve injuries. Injuries resulted from lymph node biopsies in the posterior cervical triangle in eight patients and posterior foss surgery in one. Eight patients lost the ability to abduct their arm but could still shrug their shoulder, a pattern that resulted in an incorrect initial diagnosis in five patients. The average delay from injury to referral was 8 months. Seven patients underwent nerve exploration an average of 9.7 months after injury. Five had transected nerves that could be repaired; three of these patients required a nerve graft. Pain was greatly relieved in the five patients who had severe pain before surgery, and weakened shoulder abduction improved in four of six patients. Nerve exploration should be considered when the patient's clinical exam does not improve within 3 months of injury. Nerve repair frequently reduces pain and improves shoulder abduction, even 12 months after injury.