We conducted a case-control genome-wide association study (GWAS) of human longevity, comparing 664,472 autosomal SNPs in 763 long-lived individuals (LLI; mean age: 99.7 years) and 1085 controls (mean age: 60.2 years) from Germany. Only one association, namely that of SNP rs4420638 near the APOC1 gene, achieved genome-wide significance (allele-based P=1.8×10(-10)). However, logistic regression analysis revealed that this association, which was replicated in an independent German sample, is fully explicable by linkage disequilibrium with the APOE allele ɛ4, the only variant hitherto established as a major genetic determinant of survival into old age. Our GWAS failed to identify any additional autosomal susceptibility genes. One explanation for this lack of success in our study would be that GWAS provide only limited statistical power for a polygenic phenotype with loci of small effect such as human longevity. A recent GWAS in Dutch LLI independently confirmed the APOE-longevity association, thus strengthening the conclusion that this locus is a very, if not the most, important genetic factor influencing longevity.