This article outlines current evidence and indications for electrocardiographic monitoring in documenting subclinical atrial fibrillation (AF) in patients with cryptogenic stroke. Longer monitoring improves detection rates of subclinical AF. Incorporation of risk factors predicting patients at higher risk of stroke can be used to target populations suitable for longer-term monitoring. Although longer duration of AF is expected to increase the risk of stroke, the exact cutoff for duration of clinical significance is not yet established. It seems probable that a combination of clinical risk factors and duration of AF will provide the best prediction of future clinical stroke.