We report 2 patients with unilateral pulmonary edema after heart surgery who were successfully treated using venovenous extracorporeal membrane oxygenation (VV ECMO). Case 1 : A 35-year-old woman presented with dyspnea. Echocardiography showed severe mitral regurgitation (MR) and tricuspid regurgitation (TR) and therefore, mitral valve plasty (MVP) and tricuspid annular plasty (TAP) were performed via right thoracotomy. After weaning from cardiopulmonary bypass, respiratory failure occurred with expectoration of foamy sputum and it was difficult to maintain oxygenation. Therefore, we performed VV ECMO to maintain oxygenation. A chest X-ray film after surgery showed ipsilateral pulmonary edema. After weaning from VV ECMO, deep venous thrombosis occurred and therefore we inserted an IVC filter. Case 2 : A 67-year-old man, who had previously received aortic valve replacement experienced dyspnea and visited our hospital. Echocardiography showed an aortic root abscess, and therefore Bentall operation was performed. After weaning from cardiopulmonary bypass, oxygenation was difficult to maintain, and therefore we performed VV ECMO. A chest X-ray film post operatively showed right ipsilateral pulmonary edema. The patient was weaned from VV ECMO 5 days post operatively and was discharged 60 days post operatively. We believe that VV ECMO can be beneficial for patients with respiratory failure after heart surgery, but complications related to this approach such as DVT should also be considered.