We retrospectively collected data concerning the treatment outcome of noninvasive positive pressure ventilation (NPPV) therapy for patients of acute exacerbations of chronic obstructive pulmonary disease (COPD) with hypercapnic respiratory failure who were admitted to our hospital from January 2004 to January 2008. A case of incomplete treatment was defined as difficulty in NPPV continuation, shift to intubation, or death during NPPV; the remaining cases were classified as completed treatments. Further, patient characteristics, respiratory status at the initiation of NPPV, and laboratory data were investigated to determine whether the treatment was in fact completed. In this study, we examined 47 patients, and NPPV was completed in 41 (completed rate, 87%). Further, of the 41 completed cases, 32 (78%) exhibited withdrawal from NPPV. When the completed and incompleted groups were compared, no significant differences were observed in patient characteristics and places of NPPV initiation; however, a high rate of impaired consciousness was observed in the incompleted group. Further, pH and PaCO₂ were significantly improved 1 h after NPPV initiation in the completed group. In this investigation at our hospital, we recognized that NPPV therapy was effective for acute exacerbations of COPD, as the guidelines recommended, and the level of consciousness at NPPV initiation and arterial blood gas analyses at 1 h after the initiation of NPPV were the predictors of treatment outcomes.