Anticoagulants are widely used to prevent and treat venous thromboembolism, prevent stroke in atrial fibrillation, and manage acute coronary syndrome. These drugs are often used in elderly patients, who commonly have renal impairment, comorbidities, and polypharmacy. Renal impairment is a risk factor for bleeding and thrombosis during anticoagulant therapy and can influence the balance between the safety and efficacy of such agents. Some of the more established anticoagulants, such as the low-molecular-weight heparins, warfarin, and fondaparinux, are contraindicated for use in patients with severe renal impairment. Of the new oral anticoagulants, dabigatran etexilate, rivaroxaban, and apixaban are at the most advanced stages of development. Dabigatran requires dose adjustment in patients with moderate renal impairment and is contraindicated in patients with severe renal impairment. Rivaroxaban can be administered as a fixed dose for the prevention of venous thromboembolism in patients with moderate renal impairment and should be used with caution in patients with severe renal impairment. Apixaban excretion is also partly dependent on renal function, although the impact of renal insufficiency has not been determined. Additional data on the safety of chronic dosing of the newer oral anticoagulants in renal impairment are awaited.