Longevity is a multifaceted trait in which variety of genes and environmental factors are involved. Newly, the role of vitamin D has been revived regarding its potential advantage on delaying the aging process. Vitamin D exerts its effect through vitamin D receptor (VDR). VDR-FokI is the only polymorphism which alters the VDR length. We examined the frequency of FokI genotypes in old age population as compared to young adults to determine the discerning genotype of FokI polymorphism leading to longer living. In addition, to highlight the position of FokІ polymorphism in quality of life; a cognitive function assessment was performed. 728 participants participated in this study of which 166 individuals were elderly residents of Kahrizak Charity Foundation. The rest were participants of Iranian Multicenter Osteoporosis Study (IMOS). Genomic DNA was extracted from peripheral blood and VDR genotype was detected by the polymerase chain reaction. The participants in the elderly group underwent a cognitive function assessment. Cognitive function was measured with the mini mental state examination (MMSE). Data were analyzed by SPSS 16.5. The prevalence of ff genotype showed 48% decrease in elderly population as compared to young adults (P=0.06). In addition, F allele was over-represented in the elderly group as compared to controls (P=0.05). Also, "FF" participants of elderly group had higher MMSE as compared to "ff" genotype (18.16Vs17.12). Our data suggest that single nucleotide polymorphisms (SNPs) in FokI may be possibly involved in longevity and cognitive function.