BACKGROUND: Even though surgery and anesthesia give stress to patients, adequate anesthesia could attenuate stress reactions and minimize side effects from these reactions. Abnormal glucose homeostasis is well documented side effect during anesthesia, especially when inhalational anesthetics are used. We planned this study to investigate and compare the effects of two popular anesthetics-between propofol, intravenous anesthetics, and enflurane, inhalational agents on blood glucose level. METHODS: Adult patients free of diabetes mellitus and any other endocrine disease were randomly allocated into two groups. In both groups, anesthesia was induced with 2.5% pentothal sodium 5 mg/kg and succinylcholine 1 mg/kg. After intubation, propofol 6~10 mg/kg with 50 % N2O-O2 mixture 4 liter were used for maintenance in one group (Group P). In other group, enflurane 1.5~2% with 50% N2O-O2 mixture 4 liter were used (Group E). Hartmann's solutions were used for maintenance fluid in both groups. Blood glucose levels were measured at preintubation period, postintubation 5, 10, 15 minutes and just-preincision period. Blood glucose level at admission was regarded as control value and statistical analysis was done by Student's t-test. RESULTS: In group E, there was significant increase of the blood glucose level about 23 minutes after induction but in group P, there was no significant increase of glucose level during entire experimental time. Blood glucose levels were higher from postintubation 5 minutes to just-preincision period with statistical significance in group E than group P. CONCLUSIONS: Propofol maintained stable blood glucose level compared to enflurane during general anesthesia.