The author reports the comparative effects of 2 local anesthetic agents injected into the epidural space: 1% etidocaine and 0.5% bupivacaine, both containing epinephrine (5 microgram/ml). Twenty ml of one of these solutions were administered under double-blind conditions to 40 patients undergoing orthopedic, urological, gynecological or general surgery. The onset of analgesia, as determined by the "pin-prick test" was more rapid after 1% etidocaine than after 0.5% bupivacaine. The duration of analgesia, the return of sensation and the extent and intensity of the sensory blockade were identical for both drugs. After etidocaine, motor block occurred more often, was more complete and developed more rapidly than after bupivacaine. The incidence of peroperative and postoperative complications was comparable in both groups.