To investigate the rate of deep vein thrombosis (DVT) after laparoscopic surgery, 50 patients underwent bilateral phlebography 7-11 days after laparoscopic cholecystectomy (LC). All received thromboembolism prophylaxis, either low molecular weight heparin (LMWH) or dextran. Three patients were converted to open cholecystectomy. D-dimer was investigated preoperatively, on day 1 and on the day of phlebography. One asymptomatic DVT was found. One phlebogram was incomplete. Seven phlebograms were not optimal but of sufficient quality to rule out DVT. The frequency of DVT was thus 1 of 49 or 2.0% (95% confidence interval, 0-6.0%). No anticoagulants were prescribed after discharge. No patient developed late thromboembolic complications. D-dimer values increased significantly at day 1 and were further increased at the time of phlebography. The frequency of phlebographical DVTs thus seems to be low despite prophylaxis of questionable efficacy. The D-dimer values, however, suggest that the effects of LC on coagulation/fibrinolysis have a duration of longer than 1 week.