Background/aim: Noninvasive mechanical ventilation (NIMV) is an approach to prevent complications in acute respiratory failure. In this study we aimed to compare the efficacy of a full face mask and a helmet in chronic obstructive pulmonary disease (COPD). Materials and methods: Fifty patients were divided randomly into 2 groups as full face mask (Group F) and helmet (Group H). Demographic data, forced expiratory volume at 1 s (FEV1), additional disease, hemodynamic parameters, respiratory rate, APACHE II score, peripheral O-2 saturation (SpO(2)), arterial blood gases (ABG), patient tolerance scale (PTS) score, and fraction of inspired oxygen (FiO(2)) were recorded. Parameters were recorded as follows: 20 min before the NIMV; every 30 min of NIMV until 120 min; 30 min, 24 h, and 48 h after NIMV; and prior to intensive care unit discharge. Results: The SpO(2), PTS, ABG, complication rate, and APACHE II scores were not different between the groups (P > 0.05). The decrease in PaCO2 was statistically significant at 60 min in Group F (P < 0.05), and there was no statistical difference in Group H (P < 0.05) according to initial PaCO2 values. Conclusion: Both masks are efficient in improving the patients' outcome in COPD, but the decrease in PaCO2 in the helmet group was slower than in the full face mask group.