This study intended to investigate the volume of respiration according to the postoperative time and positions among the upper abdominal surgery patients. Tidal volume and vital capacity were measured in three positions-supine, left lateral and sitting position-at preoperatively, 12 hours postoperatively and 36 hours postoperatively. Thirteen male and seven female patients who were admitted for elective abdominal surgery under general anesthesia were the subjects of the study. Those patients with cardiopulmonary problems, obesity and smoking habit were excluded from the study. The study was conducted from March 15 to June 30, 1985 in Seoul National University Hospital. Tidal volume and vital capacity were measured by Wright spirometer in various positions at preoperatively, 12 hours postoperatively and 36 hours postoperatively. The results were as following: 1) Vital capacity was significantly decreased at 12 hours preperatively and 36 hours postoperatively than preoperatively. Vital capacity was not significantly different in Various positions, but sitting position revealed better than left lateral and supine position. Tidal volume was not significantly different in each position. 2) Male patients showed significantly higher than female patients in tidal volume and vital capacity. Vital Capacity was not significantly different by sex in each position, but vital capacity was higher in sitting position than in lateral and supire position. 3) There was not significantly different in tidal volume and vital capacity according to the type of incision and positions, vital capacity was higher in sitting positionthan in left lateral and supine position.