Objective To formulate management guidelines for blunt vertebral arterial injury (BVI). Summary Background Data Compared with carotid arterial injuries, BVIs have been considered innocuous. Although screening for BVI has been advocated, particularly in patients with cervical spine injuries, the appropriate therapy of lesions is controversial. Methods In 1996 an aggressive arteriographic screening protocol for blunt cerebrovascular injuries was initiated. A prospective database of all screened patients has been maintained. Analysis of injury mechanisms and patterns, BVI grades, treatment, and outcomes was performed. Results Thirty-eight patients (0.53% of blunt trauma admissions) were diagnosed with 47 BVIs during a 3.5-year period. Motor vehicle crash was the most common mechanism, and associated injuries were common. Cervical spine injuries were present in 71% of patients, but there was no predilection for cervical vertebral level or fracture pattern. The incidence of posterior circulation stroke was 24%, and the BVI-attributable death rate was 8%. Stroke incidence and neurologic outcome were independent of BVI injury grade. In patients treated with systemic heparin, fewer overall had a poor neurologic outcome, and fewer had a poor outcome after stroke. Trends associated with heparin therapy included fewer injuries progressing to a higher injury grade, fewer patients in whom stroke developed, and fewer patients deteriorating neurologically from diagnosis to discharge. Conclusions Blunt vertebral arterial injuries are more common than previously reported. Screening patients based on injury mechanisms and patterns will diagnose asymptomatic injuries, allowing the institution of therapy before stroke. Systemic anticoagulation appears to be effective therapy: it is associated with improved neurologic outcome in patients with and without stroke, and it appears to prevent progression to a higher injury grade, stroke, and deterioration in neurologic status.