INTRODUCTION: Inflammation and acute phase reactions lead to altered high-density lipoprotein cholesterol (HDL-C) concentrations. This study aimed to evaluate HDL-C levels in community-acquired pneumonia (CAP) and to determine the predictive value of disease severity in CAP. METHODS: In this prospective cross sectional study was conducted in the Department of Pulmonary Diseases. One hundred twenty-five adult patients with CAP were included in the study. Patients were classified into three groups as follows: Group 1; outpatients, Group 2; hospitalized patients and Group 3; patients admitted to the intensive care unit. C-reactive protein (CRP), procalcitonin (PCT) and HDL-C levels were evaluated at baseline, 7th and 30th days in all CAP patients. The relationship between CRP, PCT and HDL-C levels was investigated. Diagnostic performance of baseline HDL-C levels was assessed using receiver-operating characteristic (ROC) curve analyses. Results: HDL-C levels were found to be decreased in all groups compared to their normal ranges. There was a significantly negative correlation between HDL-C and CRP and PCT (Spearman’s r= -0.557, r= -0.841, respectively; p< 0.001). The sensitivity and specificity of HDL-C cut-off value were 0.738 (95% CI: 0.580-0.861) and 0.875 (95% CI: 0.732-0.958), with an overall accuracy of 0.861 (95% CI: 0.728-0.935). DISCUSSION AND CONCLUSION: HDL-C levels can be used as an acute phase reactant in patients with CAP.