Intrathoracic lipomas are rare, benign neoplasms of unknown origin, with symptoms depending primarily on their location and size. They frequently represent on incidental roentgenographic finding and are clinically significant in that they may simulate malignant tumors and, when located endobronchially, may cause irreparable lung damage. Three cases of intrathoracic neoplasms are reported herein, and the English literature on the subject reviewed. In some cases, bronchoscopic examination may yield the diagnosis of endobronchial lipoma but, in general, thoracotomy is required for diagnosis. A more complete classification is suggested and the preferred mode of treatment is discussed.