Embryonal carcinoma of the mediastinum is a very uncommon disease. This is a report of an embryonal carcinoma in the mediastinum found in a 25 years old Korean male patient who had been suffering from chest pain and intractable coughing for 6 months. 5 weeks prior to this admission hemoptysis and high fever were followed. Right exploratory thoracotomy was performed under the impression of a mediastinal tumor, but found to be unresectable. Irradiation therapy was tried, but no response was observed. Patient expired on 78th day postoperatively.[KTCS 1978;3:364-367]