This article presents a case of a 43-year-old man with paradoxical embolism. The patient had simultaneous deep venous thrombosis, pulmonary embolism and bilateral limb-threatening arterial occlusions. The unifying diagnosis was paradoxical embolism through a previously undetected atrial septal defect. Suggestions for the evaluation and emergency management of paradoxical embolism are outlined, and the literature is briefly reviewed.