In the present study we have compared the incidence and degree of hypoxemia during the early postoperative period and for the first 3 nights after operation occurring after the administration of total intravenous anesthesia with propofol versus inhalation anesthesia with nitrous oxide and isoflurane. We studied 50 consecutive non-obese patients, ages 25-65, ASA I-II, who were scheduled for elective cholecystectomy. Patients received randomly either total intravenous anesthesia with propofol (24 patients) or inhalation anesthesia with nitrous oxide and isoflurane (26 patients). Oxygen saturation was continuously recorded on the night before surgery, for 8 hours after extubation (early postoperative period) and during the first, second and third nights after operation. In the early postoperative period we found statistically significant higher values of mean (P<0.05) and minimum (P<0.01) SpO2 in patients who received total intravenous anesthesia compared to patients in whom inhalation anesthesia was used. Moreover, in the early postoperative period, 4 (16.7%) patients of the intravenous anesthesia group versus 11 (42.3%) patients of the inhalation anesthesia group had at least 1 hypoxemic event (P<0.05). We conclude that the incidence and degree of hypoxemia in the early postoperative period is significantly less when total intravenous anesthesia with propofol is used.