It is well known that there is impaired glucose tolerance after open abdominal surgery. We have investigated the effect on insulin sensitivity of laparoscopic cholecystectomy. Eight non-diabetic patients aged 51 +/- 3.5 years were studied pre and postoperatively. Insulin sensitivity measured by the short insulin tolerance test (ITT) was expressed as % disappearance of glucose per minute (KITT). Preoperative fasting blood glucose was 4.7 +/- 0.15 mmol/l compared with postoperative fasting blood glucose of 5.7 +/- 0.31 mmol/l (p = 0.02). Fasting insulin levels were 8.4 +/- 1.6 mU/l preoperatively compared to 30.0 +/- 9.3 mU/l postoperatively (p = 0.1 NS). KITT was 2.29 +/- 0.2% min-1 (range 1.0-3.03) preoperatively with 1.11 +/- 0.25% min-1 (range 0.13-1.97) postoperatively (p = 0.02). Hence marked insulin resistance is a consequence of major abdominal surgery irrespective of surgical technique.