We have analyzed the radiographic and computed tomographic (CT) appearance of thoracostomy (chest) tubes inadvertently placed into the lungs. We have studied the clinical sequela of such malpositioning and discussed treatment options. Cases were collected from chest CT log book reports between January 1998 and January 31, 2005 which indicated or suggested intrapulmonary thoracostomy tube placement. CT scans were reviewed by the authors. The chest radiographs and medical records--including thoracic surgical reports--of those patients whose scans demonstrated intrapulmonary tube placement or indeterminate tube location were reviewed. Fifty patients, in whom 51 thoracostomy tubes were placed into the lungs, are included in this series. None of these tubes were described as intrapulmonary on reports of chest radiographs done before CT scanning. In 13 patients (26%), thoracostomy tube placements produced immediate improvement in pleural abnormalities. Dramatic increase or development of chest wall emphysema or pneumothorax was noted in 4 (8%) patients after tube placement. Twenty-five patients (50%) demonstrated either abrupt or gradual increase in pulmonary or pleural opacity on postplacement chest radiographs. Twenty-one (42%) had no apparent clinical complications. Thirteen (26%) had either prolonged air leaks or recurrent pneumothorax. Ten (20%) developed pneumonia. Retained hemothorax or empyema occurred in 8 (16%). Twelve patients (24%) required subsequent thoracic surgery. Intrapulmonary placement of thoracostomy tubes is probably more common than previously reported. This possibility should be considered when radiographs and CT scans are evaluated.