Pulmonary vein thrombosis is a rare disease but can cause severe complications. However, pathophysiology of this entity is not fully understood. We report a case of mechanical thrombectomy for acute ischemic stroke arising from thrombus of the left superior pulmonary vein stump after left pneumonectomy. A 67-year-old male without atrial fibrillation presented with middle cerebral artery occlusion 11 days after left pneumonectomy. Contrast-enhanced computed tomography showed thrombus in the left superior pulmonary vein stump. He received mechanical thrombectomy and had a good postoperative course. The retrieved embolus was macroscopically red thrombus and histological examination revealed that the embolus consisted of fibrin and erythrocyte-rich thrombus. Thrombus formation in a pulmonary vein stump after lung resection may be an embolic source of AIS. Mechanical thrombectomy and anticoagulation is effective for the treatment of this pathology.