The epsilon 4 (ε4) and epsilon 2 (ε2) alleles of the apolipoprotein gene (APOE) located on chromosome 19 have been associated with increased and decreased risk for Alzheimer disease (AD) in older adults, respectively. However, there is a dearth of studies examining the relation ofAPOEpolymorphism with cognitive functioning among community-dwelling ethnic minority elderly. This study examined the risk for cognitive impairment associated with theAPOEε4 and ε2 alleles in a community-based cohort of non-Hispanic white (NHW; N = 739) and white Hispanics (WH; N=321). All patients were recruited consecutively from a memory-screening program and evaluated using standardized assessment procedures. Cognitive impairment was classified according to an age and education adjusted Folstein Mini-Mental State Exam (MMSAdj) score of less than 24. The results indicated theAPOEε4 allele was associated with increased risk for cognitive dysfunction in NHW and WH after controlling for the effects of age, education, and gender. This risk was generally observed to be dose-dependent, with greater risk among ε4 homozygotes in relation to ε4 heterozygotes. The ε2 allele ofAPOEdid not confer decreased risk for cognitive impairment among NHW and WH. This study supports the relation ofAPOEpolymorphism to cognitive dysfunction among two ethnic populations residing in the community.