BACKGROUND Low plasma concentrations of high-density lipoprotein (HDL) are associated with increased risk of cardiovascular disease. However, recently several studies have questioned the protective role of high plasma HDL levels. OBJECTIVE This study was designed to evaluate HDL functions in women with high plasma HDL cholesterol and very low risk profile with relation to subclinical carotid atherosclerosis (ATS). METHODS Included were 158 middle-aged women with plasma HDL >60 mg/dL and Framingham risk score <7% who had B-mode ultrasound of the carotid arteries. Subclinical ATS was determined by the presence of plaques and/or intima-media thickness (IMT) >1.0 mm. RESULTS ATS was observed in 51 women, with the majority (n=41) having carotid plaques, some with advanced morphology. In a multivariable model analysis, each, HDL or age, were independently associated with increased prevalence of ATS. Odds ratios for ATS were 3.1 and 2.5 greater for age>60 years and HDL >70 mg/dL, respectively. None of HDL functions determined by its antioxidative properties, reverse-cholesterol transport, or activities of HDL-associated enzyme were different between -ATS and +ATS. C-reactive protein was similar in both groups. CONCLUSION Subclinical carotid ATS is present in one-third of middle-aged women independently of conventional risk factors. A greater ATS prevalence was associated with very high HDL values. We could not find association between ATS and HDL dysfunction.