A case of benign, cystic intrapulmonary teratoma occurring in the right lobe of a 22-year old female is described with grossly and microscopically findings. The connection between the tumor and the segmental bronchus, together with the absence of germ cell neoplasms in other locations, clearly established the true intrapulmonary nature of the lesion. The unusual finding of thymic tissue within the wall supports the possible origin from the third pharyngeal pouch.