This study compared the effect of general anesthesia or regional vertebral analgesia (subarachnoid or epidural) on postoperative cognitive function in 60 young adult (group A) and 60 elderly (group E) patients undergoing orthopedic and urologic surgery. Wechsler Adult Intelligence Scale-Revised for cognitive functions assessment was done preoperatively, and postoperatively; one day and three days after surgery. Variations in heart rate, blood pressure, arterial oxygen and carbon dioxide tensions, and pH as well as serum bicarbonate, sodium and potassium levels, were assessed at the same time intervals. They did not show any significant change from the preoperative levels. Cognitive functions, one and three days after surgery, did not change significantly in young adult patients after either general or regional vertebral nor in elderly patients who received regional regional vertebral, as compared with the preoperative levels. Only elderly patients who received general anesthesia had significant decline in cognitive function one day after surgery. It significantly improved on the third postoperative day but still was significantly less than the preoperative level. Moreover, significantly better WAIS-R Scores were found in the elderly group one and three days after spinal anesthesia than after general anesthesia. The results indicate that general anesthesia poses a significant risk for the occurrence of early postoperative cognitive dysfunction in elderly patients that can persist for 3 day after surgery. Regional vertebral analgesia is advantageous over general anesthesia for elderly patients in terms of a better postoperative neuropsychological functioning.