Background: The effect of underlying chronic obstructive pulmonary disease (COPD) on coronavirus disease 2019(COVID-19) during a pandemic is controversial. The purpose of this study was to examine the prognosis of COVID-19according to the underlying COPD. Methods: COVID-19 patients were assessed using nationwide health insurance data. Comorbidities were evaluated using themodified Charlson Comorbidity Index (mCCI) which excluded COPD from conventional CCI scores. Baseline characteristicswere assessed. Univariable and multiple logistic and linear regression analyses were performed to determine effects ofvariables on clinical outcomes. Ages, sex, mCCI, socioeconomic status, and underlying COPD were selected as variables. Results: COPD patients showed older age (71.3±11.6 years vs. 47.7±19.1 years, p<0.001), higher mCCI (2.6±1.9 vs. 0.8±1.3,p<0.001), and higher mortality (22.9% vs. 3.2%, p<0.001) than non-COPD patients. The intensive care unit admission rateand hospital length of stay were not significantly different between the two groups. All variables were associated withmortality in univariate analysis. However, underlying COPD was not associated with mortality unlike other variables inthe adjusted analysis. Older age (odds ratio [OR], 1.12; 95% confidence interval [CI], 1.11–1.14; p<0.001), male sex (OR,2.29; 95% CI, 1.67–3.12; p<0.001), higher mCCI (OR, 1.30; 95% CI, 1.20–1.41; p<0.001), and medical aid insurance (OR,1.55; 95% CI, 1.03–2.32; p=0.035) were associated with mortality. Conclusion: Underlying COPD is not associated with a poor prognosis of COVID-19.