The aim of this study was to examine the fibrinolytic activity in laparoscopic cholecystectomy (LC) to determine whether changes occur that might indicate a greater risk of thrombosis. The study was carried out in 20 patients who had undergone laparoscopic surgery for cholelithiasis without complications. The average age was 59.4 years (34-77 years). Seventy-five percent were women. The mean operating time was 70 minutes (35-120 minutes). Pneumoperitoneum at 14 mm Hg was maintained in all patients, and they were in 30 degrees reverse Trendelenburg position. Postoperative mobilization was obtained before 24 hours, and patients were discharged 48 hours after surgery. The control group was composed of 12 patients, evenly distributed by age, sex, and length of surgery, who had undergone Bassini herniorrhaphy without complications or relapses. The following hemostatic parameters were studied: plasma fibrinolytic activity (PFA), euglobulin fibrinolytic activity (EFA), tissue-type plasminogen activator (t-PA), fast-acting plasminogen activator inhibitor-1 (PAI-1), and D-dimer (D-D). Samples were obtained at the following times: (1) under basal conditions the day before surgery, (2) preoperatively, (3) at the end of surgery, (4) 24 hours after surgery, and (5) on the seventh day following surgery. No patient had clinical manifestations of thromboembolic disease immediately after surgery or during an average follow-up period of 16 months (range 15-18 months). Analysis of the results of global fibrinolysis showed that fibrinolytic activity was enhanced only in the postoperative period (third sample) of the LC patients. The fraction of euglobulins enhances fibrinolytic activity in both groups in the third sample with regard to the other determinations; the LC patients showed a higher degree of significance (p<0.005). A significant increase of postoperative t-PA in both groups was found, being more significant in the LC group (p<0.005). In the PAI-1 values, no significant differences existed between either determinations or groups. A significant increase in D-dimer (p<0.05) occurred in the immediate postoperative period (third sample) and 24 hours later (fourth sample), returning to normal basal values on the seventh day. No significant differences were found between the two groups. These results seem to indicate that LC produces an increase in the fibrinolytic activity in plasma as a result of the liberation of tissue plasminogen activator from the venous endothelium, which could indicate hypocoagulability during the immediate postoperative period and, therefore, signify less thrombotic risk for patients undergoing this procedure.