Colorectal surgery is associated with a high risk of perioperative venous thromboembolism (VTE), and this risk is especially high following colorectal cancer resection and surgery for inflammatory bowel disease. Previous analyses of large databases have reported the incidence of postoperative VTE in this population to be approximately 1.1%-2.5%. Therefore, to minimize this risk, patients should be offered appropriate prophylaxis, which may involve a combination of mechanical and pharmacologic prophylaxis with low-dose unfractionated heparin or low molecular weight heparin as recommended by several guidelines. Prior to initiation of treatment, appropriate risk stratification should be performed according to the patients' basic and disease-related as well as procedure-related risk factors, and post-operative factors. Furthermore, a risk-benefit calculation that takes into account patients' VTE and bleeding risk should be performed prior to starting pharmacologic prophylaxis and to help determine the duration of treatment.