Venous thromboembolism (VTE) is a frequent complication in patients with cancer and is associated with significant morbidity and mortality. The use of anticoagulants for the prevention and treatment of VTE in this population is challenging given the high risk of both recurrent VTE and bleeding complications. Thromboprophylaxis with subcutaneous low-molecular-weight heparin (LMWH) is recommended in cancer patients hospitalized for an acute medical illness and in those undergoing major surgery. In ambulatory cancer patients with or without central venous catheters, routine thromboprophylaxis is not recommended because of the relatively low benefit-to-risk ratio. To identify cancer outpatients at very high risk of VTE who may benefit from thromboprophylaxis, VTE risk stratification tools based on tumour type, clinical parameters, or coagulation biomarkers have been proposed, but their clinical utility needs validation. The mainstay of treatment for cancer-associated VTE is LMWH for at least 6 months or longer in case of active disease. The same initial and long-term treatment for incidental VTE as for symptomatic VTE can be suggested while awaiting additional studies in this area.