to explore the relationship between blood lipids/lipoproteins and cognitive function in the Chinese oldest-old. multivariate statistical analysis using cross-sectional data. community-based setting in longevity areas in China. eight hundred and thirty-six subjects aged 80 and older were included in the sample. plasma total cholesterol, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, blood pressure and fasting plasma glucose were measured and information about demographics and lifestyle was collected. Cognitive status was assessed using the Mini-Mental State Examination (MMSE). cumulative logit model analysis showed that triglyceride was significantly negatively associated with cognitive impairment. By general linear modelling, there was a significant linear trend of MMSE scores with the level of triglyceride, but not with levels of cholesterol after adjustment. The odds ratio (OR) of cognitive impairment (MMSE score < 18) was significantly reduced for the highest quartile of plasma triglyceride concentration (OR: 0.52, 95% CI: 0.33-0.84), but not for the second or third quartile, compared with the lowest quartile (adjusted models). There were no significant associations between cognitive impairment and cholesterol. we concluded that high normal plasma triglyceride was associated with preservation of cognitive function while lower concentrations were not in the Chinese oldest-old.