Embolism of cardiac origin accounts for about one fifth of ischaemic strokes. Strokes due to cardioembolism are in general severe and prone to early recurrence. The risk of long term recurrence and mortality are high after a cardio-embolic stroke. Cardioembolism can be reliably predicted on clinical grounds but is difficult to document. MRI, transcranial doppler, echocardiogram, Holter monitoring, and electrophysiological studies increase our ability to identify the source of cardioembolism. Non-valvular atrial fibrillation is the commonest cause of cardioembolic stroke. Despite its enormous preventive potential, continuous oral anticoagulation is prescribed for less than half of patients with atrial fibrillation who have risk factors for cardio-embolism and no contraindications for anticoagulation. Alternatives to oral anticoagulation in this setting include safer and easier to use antithrombotic drugs and definitive treatment of atrial fibrillation. Available evidence does not support routine immediate anticoagulation of acute cardioembolic stroke.