Noninvasive positive-pressure ventilation (NPPV) is increasingly being used in the care of patients suffering acute respiratory failure. High-level evidence supports the use of NPPV to treat exacerbation of chronic obstructive pulmonary disease (COPD). NPPV has also been successfully used with selected patients suffering acute hypoxemic respiratory failure and to allow earlier extubation of mechanically ventilated COPD patients. The evidence for NPPV for acute cardiogenic pulmonary edema is inconclusive. With selected patients NPPV decreases the rate of intubation, mortality, and nosocomial pneumonia. Predictors of NPPV failure include greater severity of illness, lower level of consciousness, lower pH, more air leak around the patient-mask interface, greater quantity of secretions, poor initial response to NPPV, and the presence of pneumonia. NPPV obviates intubation in > 50% of appropriately selected patients. Both nasal and oronasal interfaces have been successfully used to apply NPPV, but the oronasal interface is often preferred for acute respiratory failure. Any ventilator and ventilator mode can be used to apply NPPV, but portable pressure ventilators and pressure-support mode are most commonly used. Inhaled bronchodilators can be administered during NPPV, and NPPV can be delivered with helium-oxygen mixture. Institution-specific practice guidelines may be useful to improve NPPV success.