The purpose of this communication is to describe certain roentgen findings characteristic of disease of the lingular division of the left upper lobe. Several authors (10, 12, 13) have stated that lingular lesions are difficult to diagnose roentgenographically. This has not been our experience. If certain criteria are kept in mind, a surprising number of lesions in this segment will come to light. Clinical Material Our observations are based on 31 patients with involvement of the lingula without significant disease elsewhere. Included are cases of bronchiectasis, atypical pneumonia, interstitial pneumonitis, cancer, chronic abscess, and chronic granuloma. Of the 14 cases of bronchiectasis, the majority went to surgery. Thus, there was opportunity for correlating the roentgen and surgical findings. Roentgen Findings The normal lingula is the anteromedial segment of the left upper lobe adjacent to the left heart border. Medially it borders the pericardium, and laterally it approaches the lateral pleural wall...