BACKGROUND Deep pulmonary laceration (DPL) is rare and its survival rate is low. The present study focused on the prognostic factors of DPL. METHODS The present study concerned 17 DPL patients treated in Tokai University Hospital between 1988 and 1998. The prognostic factors of DPL were compared with systolic blood pressure (SBP), PaO2, and the volume of intrathoracic blood loss. Characteristic findings of initial chest roentgenograms of DPL were investigated. RESULTS Eleven patients were saved and 6 patients died. An SBP of less than 80 mm Hg on arrival at the hospital and a blood loss of more than 1,000 mL through the chest tube within 2 hours after arrival were poor prognostic factors. Hypoxemia on arrival was not a poor prognostic factor. Chest roentgenograms showed macular infiltrative shadow with moderate lung collapse and deviation of the mediastinal shadow toward the unaffected side. Selective bronchial occlusion with a Univent prevented suffocation by intrabronchial blood. CONCLUSIONS Two poor prognostic factors of DPL are SBP less than 80 mm Hg on arrival and blood loss of more than 1,000 mL through the chest tube within 2 hours after arrival.