The medical records of 78 procedures performed on 50 spinal cord injured patients at risk for developing autonomic hyperreflexia were evaluated for blood pressure changes during anesthesia and surgery. Hypertension was arbitrarily defined as a systolic blood pressure of greater than 140 torr. The 78 procedures were divided into three groups: group A, 19 procedures in which the patient received topical anesthesia, sedation, or no anesthesia; group B, 13 procedures conducted under general anesthesia; and group C, 46 procedures carried out under spinal anesthesia. Hypertension occurred in 15 of 19 procedures (79%) in group A, in three of 13 procedures (23%) in group B, and in three of 46 procedures (7%) in group C. Group A differed significantly from group B (p = 0.011) and group C (p = 1.2 x 10−8). There was no significant difference between groups B and C (p = 0.114). Results indicate that patients at risk for autonomic hyperreflexia are protected from developing intraoperative hypertension by either general or spinal anesthesia.