In the setting of acute coronary syndromes, plasma lipids have not been defined as prognostic variables, however little research has been dedicated to this specific issue. In order to test the independent predictive value for in-hospital events of low-density lipoprotein (LDL)-cholesterol, high-density lipoprotein (HDL)-cholesterol and triglycerides measured at hospital admission, 97 individuals with unstable angina or non-ST-elevation acute myocardial infarction were evaluated. In-hospital events, defined as death, non-fatal myocardial infarction or recurrent unstable angina, were significantly predicted by HDL-cholesterol (C-statistics=0.69; 95% CI=0.55-0.83, P=0.018), contrary to LDL-cholesterol (C-statistics=0.40; 95% CI=0.24-0.56, P=0.23) and triglycerides (C-statistics=0.48; 95% CI=0.31-0.65, P=0.83). The best HDL-cholesterol cut-off point was 32 mg/dl, with a 33% incidence of events in patients with HDL-cholesterol < or =32 mg/dl, compared with only 9% in those with HDL-cholesterol>32 mg/dl (P=0.003). Logistic regression analysis showed HDL-cholesterol< or =32 mg/dl (OR=3.6; 95% CI=1.0-14; P=0.05) and TIMI Risk Score (OR=2.3; 95% CI=1.4-2.9, P=0.001) as the independent predictors of events. Furthermore, the addition of HDL-cholesterol to TIMI Risk Score improved its C-statistic from 0.81 to 0.85. In conclusion, as opposed to LDL-cholesterol and triglycerides, HDL-cholesterol level adds prognostic value to the prediction of in-hospital recurrent events during non-ST-elevation acute coronary syndromes.