Lymphangiomas are localized malformations of the lymphatic system that most commonly occur in the head and neck. However, less than 1% of all lymphangiomas are confined to the mediastinum. The standard treatment has been surgical excision, but the involvement of vital structures in the area local to the lymphangioma makes total excision virtually impossible in most cases. To our knowledge, there has been no report of mediastinal lymphangioma treated with endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). We report here the first case of safe, effective treatment of a very large mediastinal lymphangioma using EBUS-TBNA in a 29-year-old man.