This study was designed to analyze the prevalence of I405V polymorphism in the cholesteryl ester transfer protein (CETP) gene, the blood CETP concentration, the lipoprotein pattern and certain clinical endpoints in two populations, one of young and another of very old individuals. We recruited 100 healthy young adults (median age 31 years) and 100 very old subjects (median age 89 years) and analyzed their DNA for the presence of variants V and I of the CETP gene. Subjects with the V/V genotype had lower serum concentrations of CETP. The frequency of this genotype in the very old was more than double that in the young population. Young adults with the V/V genotype had a less atherogenic lipoprotein pattern [lower total and LDL cholesterol levels, lower apolipoprotein (Apo) B levels, and a lower Apo B/Apo A-I ratio] than those with the I/V or I/I genotypes. The very old subjects, particularly those with the V/V genotype, had larger LDL than the young adults. The prevalence of clinical endpoints was much lower among the very old subjects with the V/V genotype.