The most efficient strategy for combating Alzheimer's disease (AD) is to prevent the onset of clinically significant symptoms. Determining the clinical characteristics, risk factors, and indices of cognitive reserve would help in achieving this goal. The aim of this study was to determine the risk factors for AD and vascular dementia (VD) in the elderly and to highlight the importance of risk factor modification in the early diagnosis. Consecutive 1436 patients (mean age=72.7+/-6.9 years, 34.2% male) were enrolled in the study. After a comprehensive geriatric and cognitive assessment, patients were grouped as AD group (n=203), VD group (n=73) and normal cognitive status (NCS) group (n=1160). Thirty-three possibly related factors including demographic characteristics, co-existing diseases and laboratory parameters were examined. The results revealed that female sex, advanced age, depression, and intake of vitamin supplements were independent related factors for AD; whereas depression and low-density lipoprotein-cholesterol (LDL-C) were independent related factors for VD. For every geriatric patient admitted for any reason, cognitive assessment should be performed, risk factors should be determined and the patients at high risk should be followed up carefully.