The main advantage of noninvasive ventilation over conventional mechanical ventilation is in the avoidance of endotracheal intubation and its related complications. Currently, the role of noninvasive ventilation in the management of patients with acute respiratory failure is still not firmly established. We conducted a prospective study to evaluate the efficacy of nasal positive pressure ventilation in patients with acute respiratory failure. Thirty-three consecutive patients with acute failure in whom intubation and mechanical ventilation were strongly considered were included in the study. They received ventilatory support by means of BiPAP ventilatory support system and nasal mask. Physical findings and laboratory measurements were documented before and at specific intervals after initiation of support. Eighty per cent (24/30) of patients were successfully supported. Successfully supported patients tolerated the device with improved gas exchange, hence avoiding endotracheal intubation. The mean duration of support was 19.2 hours. There were major associated complications, e.g. gastric distention or aspiration.