Objective: There is no definite laboratory parameter in predicting short-term prognosis in patients with chronic obstructivepulmonary disease (COPD). Our aim was to evaluate the prognostic effect of serum blood urea nitrogen (BUN)/albumin ratioin COPD patients. Materials and Methods: A retrospective study comprising of 264 COPD patients who were in exacerbation period andselected from 4 centers was carried out. Data on demographic characteristics, disease characteristics, comorbid conditionsand short-term prognosis of patients were obtained. and analyzed. Results: The BUN/Albumin ratio was higher in patients with oxygen saturation <90% (p=0.004). There was no differencebetween global obstructive lung disease (GOLD) stages means of BUN/Albumin ratio but this rate was higher in those withinfective exacerbations (p=0.019). The BUN/albumin ratio of patients who were discharged (5.3±2.2) was significantly high er than the patients who were transferred to the intensive care unit [ICU] (11.7±6.0) (p<0.0001). The cut-off level of BUN/ albumin ratio in prediction of the need for ICU was7.2 (sensitivity 80%, specificity 85.4%) and the area under the receiveroperating characteristic (ROC) curve was 0.911 (95% CI: 0.861–0.961) (p<0.001). The cut-off level of BUN/albumin ratioin prediction of mortality was 8.1 (sensitivity 88.2%, specificity 85.4%) and the area under the ROC curve was 0.963 (95%CI: 0.930–0.995) (p<0.001). Conclusion: BUN/albumin ratio can be used as an affordable, inexpensive and practical method for determining the short term prognosis in hospitalized COPD patients. Prospective studies involving more patients are needed.