|Purpose The purpose of this study was to analyze the correlations among bone mineral density (BMD), serum lipid levels, and cognitive function in the elderly with dementia, Methods We recruited seventy elderly with dementia (men=35, women=35) to participate in the Korean mini mental state examination (K-MMSE). Their T-scores and serum lipid levels were analyzed for correlation analysis, Results The results of this study showed that there are significant correlations between cognitive function and three factors BMD, low-density lipoprotein cholesterol (LDL-C) level, and total cholesterol (TC) level, The cognitive function scores increased proportionally with BMD but were inversely proportional to LDL-C and TC levels. There were no significant relations among cognitive function, high-density lipoprotein cholesterol (HDL-C) level, and triglyceride (TG) level. Conclusion These results indicate that there is a direct proportionality between cognitive function and BMD and inverse proportionalities between cognitive function and LDL-C level and between cognitive function and TC level. Therefore, these levels can be indices for preventing and predicting dementia.