Variants of the angiotensin I converting enzyme (peptidyl-dipeptidase A) 1 (ACE1) gene and the apolipoprotein E gene (APOE) have been suggested to be associated with human longevity. We tested the association between the ACE1 insertion (I allele)/deletion (D allele) polymorphism and longevity in a population from Southern Italy and examined the impact of geographical variation on ACE1 allele frequencies on reported associations from other European countries. ACE1 and APOE genotypes were obtained on 82 centenarians and 252 middle-aged, unrelated subjects or volunteers. No statistically significant differences were found in ACE1 genotype or allele frequencies between centenarians and controls in this Southern Italian population nor was there any observed interaction with APOE alleles that are also reputed to be linked to longevity. However, decreasing gradients in ACE1*I allele frequencies, both in centenarians and controls, with concomitant increases in ACE1*D allele frequencies (particularly the ACE1*D/*D genotype) were observed to be statistically significant from Northern to Southern regions of Europe. These findings did not support the previously reported association between ACE1 polymorphism and longevity. However, there were interesting and significant differences, as one moves from Northern to Southern Europe, with regard to the distribution of ACE1 alleles. Such genetic differences in conjunction with differing environmental factors may explain in part previous results suggesting a role of this polymorphism in longevity.