Venous thrombosis, including deep vein thrombosis (DVT) and pulmonary embolism (PE), occurs at an annual incidence of about 1 per 1,000 adults. Rates increase sharply after about age 45 years, and are slightly higher in men than women in older age. Major risk factors for thrombosis, other than age, include exogenous factors such as surgery, hospitalization, immobility, trauma, pregnancy, and the puerperium and hormone use, and endogenous factors such as cancer, obesity, and inherited and acquired disorders of hypercoagulation. This review focuses on epidemiology of venous thrombosis and the general implications of this in patient management.