Noninvasive mask ventilation may be used to treat patients with impending respiratory failure. In this case series, three patients with severe chronic obstructive pulmonary disease, who required mechanical ventilation in the past, were successfully treated with nasal bi-level positive airway pressure (BiPAP). All patients tolerated BiPAP well without complications. Therefore, nasal BiPAP may be considered a treatment option for patients with severe COPD who have previously required intubation and mechanical ventilation.