Rare, inadvertent injury to the carotid artery during head and neck surgery may result in disastrous neurologic sequelae or even death. Several cases are presented and used as the stimulus for an analytical discussion of the pathogenesis and management of cerebrovascular complications following head and neck surgery. The major pathogenetic mechanisms are identified as (1) microembolism from an ulcerated plaque; (2) intravascular thrombus with occlusion; (3) unintentional ligation, laceration, or transection; (4) ligation of a dominant external carotid; and (5) transient reduction in cerebrovascular perfusion pressure. Methods for identifying and evaluating the patient at risk for developing cerebrovascular complications are discussed and recommendations are made. The central question in the management of inadvertent arterial injury concerns whether to ligate the vessel or to restore blood flow. The controversies surrounding this issue are discussed in perspective through an analysis of current physiological concepts and of the collective clinical experiences of head and neck, vascular, and neurological surgeons handling extracranial cerebrovascular occlusive disease, penetrating injuries to the carotid artery, and tumor-related carotid catastrophes. Several factors are considered critical in determining appropriate management of any individual case; these include (1) whether recognition of the injury occurs intraoperatively or postoperatively; (2) the presence and severity of neurological deficits; (3) time from the injury to its recognition; (4) a quantitative assessment of collateral circulation; (5) a history of wound contamination or radiation therapy; (6) overall prognosis. These and other considerations are organized into a working framework through which the otolaryngologist and head and neck surgeon can better understand and manage the problem of inadvertent injury to the carotid artery.