A 69-year-old man was admitted due to blood-tinged sputum. The preoperative examination revealed 5${ imes}$2.8cm sized nodular mass on left upper lobe of the lung. The patient underwent left upper lobectomy and radical Iymph node dissection under impression of lung cancer. Postoperative pathologic examination revealed as primary choriocarcinoma of the lung. The patient expired at postoperative 58 days despite meticulous postoperative care. We planned on immediate adjuvant chemotherapy but was delayed due to postoperative pneumonia and the choriocarcinoma progressed rapidly. Primary choriocarcinoma is an extremely rare clinical entity in lung cancer with no established therapeutic guidelines available. We report a case of the primary pulmonary choriocarcinoma which was diagnosed postoperatively.