Objective: To determine the occurrence rate of complications and mortality in patients with severe asthma requiring endotracheal intubation and mechanical ventilation. Design: Retrospective review of medical records from September 1982 to July 1988. Setting: Urban, teaching hospital serving primarily indigent patients. Patients: Fifty-seven adult patients with asthma requiring tracheal intubation and mechanical ventilation. Interventions: None. Measurements and Main Results: Fifty-seven patients requiring tracheal intubation and mechanical ventilation during 69 hospital admissions were identified. Medication noncompliance and upper respiratory tract infections were recorded as the most frequent precipitating events for exacerbation of asthma. Forty-nine intubations were initiated because of a clinical diagnosis of respiratory distress, but multiple indications were present in 42 admissions. One or more complications occurred in 31 episodes of endotracheal intubation and mechanical ventilation (45%). Death occurred in four (6%) of 69 admissions. Three of the four deaths occurred in patients who had a cardiorespiratory arrest before hospital admission. Conclusions: While complications occurred in 45% of patients with severe asthma requiring intubation and mechanical ventilation, the mortality rate was low. We conclude that intubation and mechanical ventilation in patients with life-threatening asthma are safe and beneficial interventions. (Crit Care Med 1993; 21:1727–1730)