As many as 20% of extubated patients require reintubation (ie, extubation failure) within 72 hours of extubation, with the exact prevalence depending on numerous factors. The pathophysiologic basis of extubation failure is often different from the cause of weaning failure. Extubation failure substantially prolongs the duration of mechanical ventilation, intensive care unit stay, and hospital stay, and substantially increases hospital mortality. Therefore, prediction of extubation outcome and prevention of extubation failure may be critically important. Unfortunately, standard weaning tests have not proven sufficiently accurate in predicting extubation outcome. New semi-objective measurements of cough strength and secretion volume can help identify patients at increased risk for extubation failure. It is important to note that mortality increases with reintubation delay, which indicates that clinical worsening may take place during the period without ventilatory support. Therefore, improved outcome may derive from rapid identification of patients at increased risk, followed by expeditious reinstitution of ventilatory support when extubation failure occurs.