Approximately 20%–25% of adults encounter metabolic syndrome (MetS) worldwide, and MetS is a risk factor for cognitive decline (CD) development. Patients with MetS have an 11.48-fold increased incidence of CD compared with those without MetS.1 Ataxia-telangiectasia mutated (ATM) gene encodes ATM kinase, which belongs to the phosphatidylinositol 3-hydroxy kinase family. Reduced ATM gene expression creates an inhibitory hippocampal function, excitatory/inhibitory imbalance, and finally CD.2 Based on the China Hainan Centenarian Cohort Study (CHCCS) performed in 18 cities and counties of Hainan, we showed that the frequency of CC genotype in single nucleotide polymorphism (SNP) rs189037 was significantly higher and that of TT genotype was significantly lower in centenarians with MetS than in those without MetS. Compared with CC and CT genotypes, TT genotype was negatively and significantly associated with MetS but not CD. This study demonstrated that mutant SNP rs189037 in ATM gene had a significantly negative association with MetS but not CD in Chinese centenarians.