This guideline is an update to “Venous Thromboembolism Prophylaxis and Treatment in Patients with Cancer: American Society of Clinical Oncology Clinical Practice Guideline Update” (2013). The guideline is for cancer patients who may be at risk for venous thromboembolism (VTE), and provides recommendations on prophylaxis and the treatment of VTE in the outpatient, inpatient, and perioperative settings. Interventions considered include mechanical and pharmacologic thromboprophylaxis and patient education. The role of inferior vena cava (IVC) filters is also discussed. Outcomes of interest include symptomatic and asymptomatic thrombotic events found on screening, major and minor bleeding, mortality (early and overall), sudden death, and adverse events.