The aim of this study was to investigate the response of cortisol, insulin and lipid parameters [serum Lipoprotein Lipase activity, choleseryl-ester transfer protein, triglycerides, total Cholesterol, High Density Lipoprotein, Free Fatty Acids] during the perioperative period in obese patients undergoing laparoscopic cholecystectomy. Twenty obese patients were included and divided in two groups. In group A (n=10) patients were anaesthetized with propofol and group B (n=10) with etomidate. Blood samples were collected before induction in anaesthesia, just after the end of the operation and at one, two and three hours postoperatively. According to our results, in both groups serum LPL activity showed a significant decrease whereas serum Free Fatty Acids a potent increase over time. Likewise, both groups did not demonstrate significant changes over time in choleseryl-ester transfer protein activity, total cholesterol, triglycerides, High Density Lipoprotein or insulin concentrations in serum. Furthermore, cortisol release was significantly inhibited in the etomidate group while substantially enhanced in propofol group. Additionally, apart of triglycerides, no difference was found between the two groups in all the lipid parameters and insulin concentrations. In conclusion, serum Free Fatty Acids levels and Lipoprotein Lipase activity demonstrated significant alterations in obese patients underwent laparoscopic cholecystectomy and this result did not seem to be related with the anaesthetic agent used for induction in anaesthesia.