Background: Aspiration of blood may cause significant morbidity during emergent endoscopy for severe upper GI bleeding. Endotracheal intubation is widely performed for airway protection in this setting, but there are few data regarding its efficacy. Methods: Outcomes were compared for intensive care unit patients with upper GI bleeding for 1 year (1988) during which prophylactic endotracheal intubation was seldom performed before endoscopy, with outcomes during a subsequent year (1992) in which endotracheal intubation was routine for airway protection before or during EGD when there was hematemesis, altered mentation, unstable cardiopulmonary status, or large amounts of blood in the proximal GI tract, or before endoscopic treatment of lesions at high risk for bleeding. Results: Background variables were similar for intensive care unit patients in 1988 (n = 101) and 1992 (n = 119) with respect to number of patients who had shock (respectively, 66.3% vs. 67.2%), cirrhosis (34.7% vs. 38.6%), variceal/portal hypertensive bleeding (22.8% vs. 33.6%), and endoscopic therapy (37.6% vs. 42.0%). Although use of endotracheal intubation specifically for EGD increased significantly between 1988 and 1992 (3.0% vs. 15.1%; p < 0.05), there were no significant changes in endotracheal intubation at any time during hospitalization (24.8% vs. 28.6%), in all EGD-related cardiopulmonary complications (5.0% vs. 3.4%), in new pulmonary infiltrates after EGD (12.9% vs. 15.1%), in mean number of intensive care unit days (7.1 vs. 6.4), or in mortality (15.9% vs. 11.8%). New infiltrates developed in 10 (48%) of 21 patients after EGD despite endotracheal intubation specifically for airway protection. However, in 1992 there were no fatal episodes of aspiration during EGD (2.0% vs. 0%; p = 0.21), no emergent post-EGD endotracheal intubation (6.0% vs. 0%; p < 0.05), and fewer in-hospital cardiopulmonary arrests (12.9% vs. 5.0%; p < 0.05). Conclusion: Frequent use of endotracheal intubation for airway protection during EGD for upper GI bleeding requiring intensive care unit admission did not significantly change the relatively high frequency of acquired pneumonia or cardiopulmonary events, but may have prevented the rare fatal episode of massive aspiration. Endotracheal intubation may benefit selected patients with upper GI bleeding, but its specific role remains unclear, and alternative methods of airway protection should be investigated.