Exacerbation of chronic obstructive pulmonary disease (COPD) is one of the frequent causes of acute respiratory failure. In our study, we aimed to compare helmet with face mask in noninvasive mechanical ventilation (NIMV) on patients who had acute respiratory failure because of exacerbation of COPD in intensive care unit (ICU). Thirty patients, taken into ICU for exacerbation of COPD, were included in the study. Patients were divided into two groups as face mask group (Group Y) and helmet group (Group H). Appropriate mechanical ventilation settings were recorded after the starting period and NIMV was applied to patients continuously for two hours with these settings. Respiratory frequency (f), blood gas (PaO(2), PaCO(2), PH) and PaO(2)/FiO(2) values and hemodynamic data of all patients were recorded periodically. Compliance of patients were evaluated with patient tolerance scale (PTS). Duration of stay of the patients in ICU and complications were also noted. Demographic characteristics of patients, mechanical ventilator settings and hemodynamic data of the patients in the two groups were found to be similar (p>0.05). Frequency values measured during NIMV are also similar at all measurement times (p>0.05). It was determined that there was a remarkable decrease in respiratory frequency, in both groups after the application of NIMV (p< 0.001). There was no difference with respect to PaO(2), PH and PaO(2)/FiO(2) values at all measurement times, between groups (p> 0.05). PaCO(2) values in the beginning were similar in both groups but PaCO(2) measured at other measurement times for group H were statistically higher compared to the other group (p< 0.05). PTC score measured at during NIMV in group H were remarkably higher (p< 0.05). Helmet developed as an alternative to face mask has a better patient tolerance and accordingly in increases success rate in NIMV. But it must be keeping mind that the decrease in PaCO(2) value is slow with helmet.