SARS-CoV-2 infection is associated with arterial and venous thrombotic complications. In a US registry of patients with COVID-19, thrombotic complications occurred in 2.6% of 229 non–critically ill hospitalised patients and in 35.3% of 170 hospitalised critically ill patients. The risk of thromboembolism in SARS-CoV-2 infection in non-hospitalised patients is unknown. Thrombotic complications include myocardial infarction (MI), ischaemic stroke, and venous thromboembolism (VTE). Autopsy findings of microthrombi in multiple organ systems, including the lungs, heart, and kidneys, suggest that thrombosis may contribute to multisystem organ dysfunction in severe COVID-19. In this article recently published in JAMA, the authors discuss diagnosis, management, and pathophysiology of arterial and venous thrombosis in COVID-19 patients.