Background : It is well established that the concentration of cholesterol in HDL (HDL-C) was iinversely associated with prevalence and death rates of CVD (cardiovascular disease). In fact, HDL-C itself does not have any antiatherosclerotic functions, instead it indicates the current amount of reverse cholesterol transport (RCT). RCT is believed to be one of the main explanations of HDL function. In animal studies, HDL function changes in inflammatory conditions by substituting Apolipoprotein AI(ApoA1) with Serum Amyloid A(SAA). On the contrary, few studies was reported in human. The aim of this study is to evaluate the RCT function of HDL in CVD status and inflammatory conditions in clinical situation. Methods: The study group comprised 1318 consecutive subjects with acute coronary syndrome(ACS, n=189) and control subjects(n=1129) visiting cardiovascular center of KUMC Guro-Hospital. ACS was defined as acute myocardial infarction and unstable angina. We measured HDL-C, ApoA1 and, HDL-c/ApoA1 ratio as markers for functional RCT status by HDL. Results: HDL-C and ApoAI showed higher values in control group than ACS group. (Control vs ACS; HDL-C 52.28 mg/dL vs 46.56 mg/dL, ApoAI 141.20mg/dL vs 129.76mg/dL, P=0.000) HDL/ApoAI also showed difference between both groups. (Control vs ACS; 0.36 vs 0.35, P<0.05) HDL/ApoAI was positively correlated with CRP level after adjusting sex, age, diabetes, smoking status and the use of statins. The regression coefficient(b) for HDL against log CRP is different from that of ApoA1 (HDL vs ApoAI; -2.532 vs -4.419) in total population. Comparing the regression coefficient(b) for ApoA1 against log CRP between control and ACS group, ApoA1 reduced more sharply in ACS group than in control. (Control vs ACS; -3.679 vs -5.356). Hypertension and diabetes also decrease RCT function. Conclusion: The dynamic status of RCT function change in accordance with CVD status and inflammation. Both HDL-C and ApoAI decrease as the CRP level increases, but slope of ApoAI reduction was stiffer than HDL-C. These findings suggest that RCT function of HDL decreases in inflammatory conditions and CVD.