Tramadol(Tridol) was developed by Grunenthal GmbH as a new non-narcotic analgesic agent. It was used as a new anesthetic agent by Stoffregen who works in Hage, West Germany, instead of neurolept-anesthetics which make sometimes cause severe post-anesthetic respiratory insufficiency. From September to December 1982, 40 cases of balanced anesthesia with controlled tramadol infusion were performed at Chung Ang Univ. Hospital. The anesthetic results were compared with 72 cases of halothane anesthesia: 1) During anesthetic induction, changes of systolic blood pressure were similar in both 2 groups, but the heart rate was stabler in the tramsdol group. 2) Tramadol has little effect on muscular relaxation. 3) Tramadol anesthesia has very rapid post-anesthetic consciousness recovery time and this little respiratory depression. 4) Post-operative pain was minor in tramadol anesthesia compared to neurolept-anesthesia. 5) The technique of use was very simple, safe and economically cheap in balanced anesthesia with controlled tramadol-infusion.