Venous thromboembolic events (deep vein thrombosis [DVT] and pulmonary embolism) are serious preventable complications associated with gynecologic surgery. Preoperative risk assessment of the individual patient will provide insight into the level of risk and the potential benefits of prophylaxis. Common risks include a history of venous thromboembolism, age, major surgery, cancer, use of oral contraceptives or hormone therapy, and obesity. Based on the presence of risk factors, the patient should be categorized into one of four risk groups and appropriate thromboprophylaxis prescribed. Randomized clinical trials in gynecologic surgery and general surgery have established the significant value of thromboprophylaxis. For moderate- and high-risk patients undergoing surgery for benign gynecologic conditions, low-dose unfractionated heparin, low molecular weight (LMW) heparins, intermittent pneumatic leg compression, and graded compression stockings all have demonstrated benefit. If using low-dose unfractionated heparin in high-risk patients, the heparin should be administered 5,000 units every 8 hours. Because DVT often begins in the perioperative period, it is important to initiate low-dose unfractionated heparin or administer the first LMW heparin dose either 2 hours preoperatively or 6 hours after the surgical procedure. Low molecular weight heparin has the advantage of being administered once daily but is more expensive than low-dose unfractionated heparin. In addition, LMW heparin has not been shown to be more effective and has similar risk of bleeding complications when compared with low-dose unfractionated heparin. In the very high-risk patient, a combination of two prophylactic methods may be advisable and continuing LMW heparin for 28 days postoperatively appears to be of added benefit.