Paradoxic embolus is uncommon. Definite diagnosis requires demonstration of thrombus astride a patent foramen ovale (PFO) in a patient presenting cerebral or peripheral arterial embolism. With current echocardiography techniques, it is now possible to identify subjects with a PFO at risk for paradoxal embolism, however, the possibility of screening rekindles debate on prophylaxis and treatment. In the present report, we describe a case involving a woman who presented acute ischemia of the lower extremities with all the pathophysiologic features of paradoxical arterial embolism.