Purpose: To compare the effects of volume and pressure support ventilation in patients with chronic obstructive pulmonary disease (COPD). Patients and Methods: The study was performed at the Medical Intensive Care Unit of Erciyes University, Medical Faculty. Twenty male patients with COPD who required ventilatory support were included in the study. Pressure regulated volume controlled mechanical ventilation was used until clinical, hemodynamic and laboratory parameters were stabilised. Then ventilator mode was switched to volume-supported ventilation (VSV). Number of breaths, peak inspiratory pressure, mean airway pressure, tidal volume (VT), blood pressure and heart rate were measured at the beginning of this mode and after two hours. Blood gases were assessed at second hour. Following this process, pressure-supported ventilation (PSV) was applied, and these parameters were measured. Results: In our study, patients supported with PSV compared with VSV ventilation showed significantly higher VT and lower airway pressure. Both VSV and PSV have similar hemodynamic effects. However, improvement of blood gases was better in PSV than VSV. Conclusion: This study showed that PSV provided more comfortable, more effective and less risky ventilation support compared with VSV.