A 25-year-old man presented with complaints of nonpleuritic, substernal chest pain, dyspnea, and decreasing exercise tolerance. His vital signs were normal, with the exception of an oxygen saturation level of 93% while breathing room air. During his assessment, he developed transient left facial droop, left arm and leg weakness, and an ataxic gait, which lasted 15 min then resolved spontaneously. Cardiac enzyme levels were elevated, and an ECG revealed T-wave inversion in leads III, aVF, V1, and V2 with evolving ST-segment elevation in leads V3 through V5. The findings of a CT scan and MRI of the head were negative; a Doppler ultrasound of the right lower extremity revealed a thrombus extending from the common femoral vein to the popliteal vein. Cardiac catheterization revealed no evidence of epicardial coronary artery disease. CT pulmonary angiography revealed bilateral pulmonary emboli. Transesophageal echocardiography (TEE) showed a 4-cm, dumbbell-shaped mass lodged in a patent foramen ovale, confirming the diagnosis of an impending paradoxical embolism. The patient was started on therapy with unfractionated heparin, and his thrombus resolved spontaneously by hospital day 5. An impending paradoxical embolism is rare but should be suspected in anyone presenting with evidence of both venous and arterial emboli. The therapeutic options include anticoagulation, thrombolysis, and surgical embolectomy. We would propose that initial treatment with anticoagulation therapy and following with serial TEEs may be appropriate therapy in an otherwise stable patient, with surgical embolectomy or thrombolysis reserved for the treatment of thrombi that do not resolve with anticoagulation therapy or for patients with clinical deterioration.