Twelve patients with a chest tube positioned in the major fissure of either lung were collected prospectively in a two-year period. In eight of these 12, there was evidence of chest tube malfunction, with poor drainage of pleural air or fluid collections; in six of these eight, placement of additional tubes or tube repositioning resulted in improved pleural drainage. In all 12, the tube had been placed through the lateral chest wall. Although tube placement in the major fissure can sometimes be suspected on the anteroposterior portable chest roentgenogram because of the tube's characteristic course, in such cases a lateral roentgenogram is not usually obtained for confirmation of location unless there is evidence of tube malfunction.