Maintenance of pneumoperitoneum to perform laparoscopic surgery with carbon dioxide (CO2) could induce hypothermia. The authors assessed the mean body temperature (MET) and changes in total body heat content (TBHC) under laparoscopic cholecystectomy. Thirty-six ASA I-II female patients underwent open cholecystectomy (Group-O, n = 18) or laparoscopic cholecystectomy (Group-L, n = 18). Esophageal temperature and four skin-surface temperatures were measured before induction and then every 10 minutes, and at arrival to the postanesthesia care unit. Operating room temperature was 22.9 +/- 1.2 degrees C. Operating time was as follows: G-O, 74 +/- 21 minutes; G-L, 94 +/- 16 minutes. After 60 minutes of surgery, decrease in TBHC was as follows: G-L = 54.9 kJ and G-O = 40.9 kJ. Decrease in MBT after 60 minutes intervention and at arrival to the postanesthesia care unit was as follows: G-L = 0.13 and 0.66 degrees C and G-O = 0.17 and 0.49 degrees C, respectively. There were no statistically significant differences between groups. Minor differences were attributed to longer surgery duration in the laparoscopic group.