Anticoagulant therapy for ischaemic stroke aims to prevent recurrent ischaemic stroke and venous thromboembolism. Several large clinical trials have provided insight into the safety and efficacy of anticoagulant therapies. Anticoagulant treatment provides no net benefit over placebo or antiplatelet therapy in patients with acute ischaemic stroke of arterial or cardiac origin, because reductions in early recurrent ischaemic events and venous thromboembolism are offset by increases in bleeding events. For patients with ischaemic stroke of cardiac origin due to atrial fibrillation, long-term warfarin treatment reduces the risk of recurrent stroke by two-thirds compared with control, and by half compared with antiplatelet therapy. New anticoagulants, such as dabigatran, rivaroxaban and apixaban, are as efficacious and safe as warfarin, and have a rapid onset of action, few drug interactions, and predictable anticoagulant effects that do not require routine monitoring. However, the anticoagulant effects of the new drugs cannot be reliably measured or rapidly reversed in the event of major non-compressible bleeding or urgent surgery. In addition, the new agents cannot be used in patients with severe renal impairment or active liver disease. Ongoing research aims to resolve these limitations, examine whether the promising results of clinical trials can be translated into clinical practice, and monitor the long-term safety of anticoagulant therapies.