The dangers of explosion hazards and operation theater contamination by inhalation anesthetics have led to a renewed interest in intravenous anesthesia. without intubation. We have reported clinical studies of Thalamonal-ketamine anesthesia under room air breathing in non-abdominal surgery in a previous paper that discussed advantages, disadvantages and usefulness. Now, we report Thalamonal-N₂O-Ketamine anesthesia with a microdrip technique and intubation in 63 patients undergoing various operations. These patients were divided into three groups by operation site: Group 1-upper abdominal, Group 2-lower abdominal and Group 3-non-aMominal surgery. These groups were subdivided, by muscle relaxants used, into pancuronium, d-tubocurarine and no relaxant groups. To minimize potential cardiovascular stimulation and postoperative sequelae, ThalamonaI was used at the beginning of anesthesia. The results were as follows: 1) The average duration of anesthesia was 153.9 minutes. The duration of anesthesia was 217.9 minutes in Group I, 121.9 minutes in Group 2 and 152.1 minutes in Group 3. 2) The average dose of ketamine-during induction was 1mg/kg/19 minutes. The average maintenance dose of ketamine was 1.8mg/kg/hr, 2.3mg/kg/hr in Group 1, 1.6mg/kg/hr in Group 2 and 1.8mg/kg/hr in Group 3. 3) The order of frequency of administration and total dose of pancuronium and d-tubocurarine was Group 1, Group 2 and Group 3. 4) The changes in vital signs after intubation and during anesthesia were insignificant clinically. 5) The average duration required from the end of operation to extubation was 10 minutes. 6) Arterial blood gas study performed preoperatively, during operation and in the recovery room in 11 patients revealed no significant changes. 7) The postanesthetic complications were pleasant dreams 18% (11), unpleasant dreams 6% (4), emergence delirium 3% (2), vomiting 6% (4) and shivering 3% (2).