Venous thromboembolism (VTE), which had been considered a relatively rare disease in Japan, has been on the increase in recent years as eating habits have become more similar to those of the West. The Ministry of Health, Labor and Welfare in Japan reported in a patient survey that there were 4,000 patients with pulmonary thromboembolism (PTE) and 1,738 deaths from PTE in 1999 increasing in about 3 times for a decade. The annual age-adjusted PTE mortality rates markedly increased in both genders in every decade and in the 1980s, women exceeded men in age-adjusted deaths and mortality rates. First of all, the Japanese Society of Pulmonary Embolism Research analyzed 309 cases of acute PTE among a total of 533 registry patients. Main risk factors were recent major surgery, cancer, prolonged immobilization, and obesity; only a few patients had coagulopathy and 36% were in cardiogenic shock at presentation. Among 110 cases of recent major surgery, PTE occurred associated with orthopedic surgery (29.1%), general surgery (21.8%), gynecological surgery (18.2%), neurosurgery (8.2%), urological surgery (5.5%), and others (17.3%). In-hospital mortality rate was 14%. The predictors of in-hospital mortality were male gender, cardiogenic shock, cancer, and prolonged immobilization. Then, perioperative PTE was investigated by Editorial Committee on Guideline for Prevention of Venous Thromboembolism by Japanese Society of Anesthesiologists since 2002. 369 cases of PTE were registered in 2002. The rate of perioperative PTE is estimated to be 0.044% (369/837,540), and the fatal rate among clinical PTE was 17.9%. 36% of the cases occurred in orthopedics, 22% in general surgery and 10% in obstetrics and gynecology. 59% of the cases did not received prophylaxis, and 52% of the cases were restricted mobility. The rate of perioperative PTE has increased to be 0.048% (440/925,260) in 2003, however, its rate has decreased to be 0.037% (411/1,126,627) in 2004 after drafting Japanese guidelines for perioperative PTE prevention. This guideline was classified by different risk factors, based on our investigations. The incidence of PTE in Japan is considered to be one level lower compared with Western populations according to ACCP (American College of Chest Physicians) guidelines. Furthermore, low molecular weight heparin (LMWH) is not covered by health insurance still now in Japan. Then, we established Japanese guidelines for PTE prophylaxis according to Japanese clinical evidences of PTE. We classified four risk groups according to ACCP guidelines. Recommended thromboprophylaxis is early mobilization for low risk group, elastic stocking (ES) or intermittent pneumatic compression (IPC) for moderate risk group, IPC or low dose unfractionated heparin (LDUH) for high risk group, and LDUH + IPC or LDUH + ES for highest risk group. And, risk group should be raised one rank in cases with any additional risks, such as obesity, advanced age, pregnancy, operation time, and other complications. Fortunately, the management fee for PTE prophylaxis was established and covered by health insurance in April 2004. Surprisingly, the incidence of perioperative PTE decreased just after this guideline was issued. Furthermore, after accumulation of further evidences and application of pharmacological agents, such as LMWH, we will establish the advanced guidelines in the future.