Longevity is written into the genes. While many so-called “longevity genes” have been identified, the reason why particular genetic variants are associated with longer lifespan has proven to be elusive. The aim of the present study was to test the hypothesis that the strongest of 3 adjacent longevity-associated single nucleotide polymorphisms –rs3794396– of the vascular endothelial growth factor receptor 1 gene,FLT1, may confer greater lifespan by protecting against mortality risk from one or more adverse medical conditions of aging – namely, hypertension, coronary heart disease (CHD), stroke, and diabetes. In a prospective population-based longitudinal study we followed 3,471 American men of Japanese ancestry living on Oahu, Hawaii, from 1965 until death or to the end of December 2019 by which time 99% had died. Cox proportional hazards models were used to assess the association ofFLT1genotype with longevity for 4 genetic models and the medical conditions. We found that, in major allele recessive and heterozygote disadvantage models, genotypeGGameliorated the risk of mortality posed by hypertension, but not that posed by having CHD, stroke or diabetes. Normotensive subjects lived longest and there was no significant effect ofFLT1genotype on their lifespan. In conclusion, the longevity-associated genotype ofFLT1may confer increased lifespan by protecting against mortality risk posed by hypertension. We suggest thatFLT1expression in individuals with longevity genotype boosts vascular endothelial resilience mechanisms to counteract hypertension-related stress in vital organs and tissues.