In this study, we sought to identify CpG sites whose methylation changes are associated with accelerated or decelerated aging using the Hannum epigenetic clock. The epigenetic age using the Hannum clock was determined for 1410 individuals aged 5 to 90 years. Cases of accelerated and decelerated aging were then distinguished on the basis of the epigenetic age differing from chronological age by more than 10 years. Comparison of these groups with a group that did not demonstrate differences between chronological and biological age revealed 912 and 52 differentially methylated CpGs, respectively. The top 29 CpGs for the accelerated and decelerated aging groups were the same. Notably, 21 CpGs were associated with accelerated aging when hypermethylated and with decelerated aging when hypomethylated. The opposite was observed for 8 CpGs. The mean size of the effect (correlation of methylation with deviation from calendar age) was r = 0.32 at p = 1E-19. The results were reliably replicated in an independent sample of 3000 individuals. The most surprising finding of the study was that the same CpGs were associated with accelerated and decelerated aging. Analysis of CpGs associated with accelerated aging showed that they were also associated with cognitive abilities, stress, atherosclerosis, obesity, and rheumatoid arthritis, but not with type 2 diabetes, leukemia, and adenoma.