In a population of general surgery patients in Western countries, there was a 19% incidence of deep vein thrombosis (DVT) and a 1.6% incidence of pulmonary embolism (PE), with 0.9% of patients experiencing fatal PE. In Japan, there was a 15.8% incidence of DVT and a 0.34% incidence of PE, with 0.08% of patients experiencing fatal PE in a population of abdominal surgery patients. The incidences of PE and fatal PE in our department were 0.11% and 0.03%, respectively. We started to use intermittent pneumatic compression (IPC) for the prophylaxis of postoperative PE in 1999 and then added elastic stockings in 2002 and low-dose unfractionated heparin (LDUH) in 2003 for prophylaxis. The incidence of PE has dropped and that of fatal PE has become 0% with the use of such prophylactic measures. When the risk of venous thromboembolism of the 15 patients who experienced PE in our department were assessed using the Japanese Guidelines for Prevention of Venous Thromboembolism, 13 patients were assessed as high risk and 2 as low risk. The mean age and mean body mass index of the 15 patients were 54 yeas old and 24.8, respectively, and PE was not limited to obese or elderly patients. Such findings appear to indicate the difficulty of risk assessment for PE. Therefore we started to use IPC, elastic stockings, and LDUH for the prophylaxis of PE and DVT for all general surgery patients from April 2004. These prophylactic measures are recommended for the highest-risk patients in the Japanese Guidelines for Prevention of Venous Thromboembolism. There have so far been no serious bleeding complications with the administration of LDUH. We will continue to observe the effects of prophylaxis and the risk of bleeding.