The aim of this study was to assess the risk of clinical thromboembolism in laparoscopic digestive surgery. From June 1992 to June 1997, 2,384 consecutive patients were studied. All received perioperative prophylaxis with low-molecular-weight heparin (LMWH), which was continued until full mobility was regained. Eight cases (0.33%) of deep venous thrombosis were noted, but there were no cases of pulmonary embolus. In six cases (five cholecystectomies with reverse Trendelenburg position and one inguinal hernia repair), release of the pneumoperitoneum took longer than 2 hours, and in two cases (one rectopexy and one sigmoid colectomy for diverticulitis), longer than 3 hours. In six of the eight cases, the diagnosis of DVT was made after LMWH had been ceased and the patient had been discharged. All cases were diagnosed before the 10th postoperative day. Pneumoperitoneum is felt to predispose to deep venous thrombosis. Long operations and reverse Trendelenburg position are further potentiating factors. Thromboprophylaxis for laparoscopy should be the same as for conventional surgery, i.e., tailored to individual risk and continued for a minimum of 7 to 10 days. We also recommend using graduated compression stockings, maintaining a relatively low insufflation pressure, keeping use of the reverse Trendelenberg position to a minimum, and intermittently releasing the pneumoperitoneum in longer procedures.