BACKGROUND: In patients with chronic obstructive pulmonary disease(COPD), it is well known that hypoxemia increases the frequency of VPB, which is associated with the poor prognosis such as sudden death. The aim of this study is to evaluate the effect of short and long-term low flow oxygen therapy on the development of VPBs in patients with COPD by correcting the hypoxemia. METHOD: In 19 patients with COPD, oxygen saturation and VPB are monitored by pulse oxymeter and 24-hour Holter EKG, with room air and the 1st and the 8th day during oxygen therapy by nasal prong (2L/min). RESULTS: The arterial oxygen saturation was significantly higher on the 1st day of oxygen therapy compared with breathing room air, and also higher on the 8th day of oxygen therapy than on the 1st day. We found that there was significant correlation between the minimal value of the arterial oxygen saturation and the mean value of the arterial oxygen saturation. The number of VPBs per hour was significantly higher on the 1st day of oxygen therapy compared with breathing room air, and also higher on the 8th day of oxygen therapy than on the 1st day. There was no significant correlation between the decrease of the frequency of VPBs and the increase of the minimal arterial oxygen saturation. But, because of the low p value as 0.056, The correlation is highly suggested. CONCLUSION: With oxygen therapy, the arterial oxygen saturation was increased and the number of VPBs was decreased, and with long-term oxygen therapy more than 7days, the number of VPBs was more decreased in patients with COPD.