Long-lived subjects have been shown to have peculiar anthropometric features (i.e. lower body mass index (BMI)) and metabolic parameters (i.e. improved insulin sensitivity). Life style and a genetic background potentially protective against the age-related metabolic derangement might contribute to such a particular phenotype. Peroxisome proliferator-activated receptor (PPAR)gamma-2 is an important regulator of adipose tissue metabolism, insulin sensitivity and inflammatory response. Thus, the potential role of genetic variability at Pro/Ala loci of PPARG gene on longevity was studied in 222 long-lived subjects and 250 aged subjects. We found a different Pro/Ala genotype frequency distribution between long-lived and aged men subjects, long-lived men having an increased frequency of Pro/Ala genotype (20 vs 8.5%); no differences was found when allele and genotype distribution of Pro/Ala gene polymorphism were analyzed in the two age group of women. Interestingly, subjects with Pro/Ala polymorphism had significantly lower BMI than Ala/Ala and Pro/Pro polymorphism. In conclusion, our study demonstrated that paraoxonase Pro/Ala gene polyporphism is associated with human longevity. Such an effect is probably due to the effect of Pro/Ala polymorphism on body composition and appears to be gender specific.