The blood gas effect of epidural analgesia supplemented with a small dose of sedatives was studied in geriatric patients over 65 years old with gastrectomy. In group A, 20 patients (mean age 72.4±4.3) were given oxygen from 20min after epidural puncture throughout the surgery, and in group B, 10 patients (71.5±4.1) were given no oxygen throughout the procedures. No significant change in blood gas was observed in either group either before or after the epidural analgesia. A small dose of sedatives, however, caused a slight fall in pH and a slight rise in PaCO_2. These changes are considered to be clinically of less importance, and in less than 20min they were restored to the previous values. In connection with patient management from the aspect of respiratory care, we consider epidural analgesia to be one of the safe methods for the anesthesia of gastrectomy in elderly patients as long as a short period of inspection on the respiratory state of the patient is given after administrating a small dose of sedatives.