The lupus anticoagulant, an acquired immunoglobulin associated with an increased tendency for thrombosis, has been linked to the occurrence of cerebral ischemia presumably related to in situ thrombosis. Cardioembolic cerebral ischemic events have rarely been reported. We encountered 2 patients with focal cerebral ischemia, substantial mitral valvular masses, and a circulating lupus anticoagulant. In each, diagnostic evaluation supported a cardioembolic etiology. These findings illustrate the need for evaluating patients with cerebral ischemic events for a cardioembolic source when a circulating lupus anticoagulant is present.