Aging is a phenomenon that affects nearly all animal species. Several studies using different systems have identified a number of processes thought to contribute to the aging phenotype. Many differentially expressed genes have been implicated, but the mechanisms governing mammalian aging (and longevity) are not yet fully understood, and the list of concerned genes is still incomplete and fragmented. Different approaches have been used to clone aging and longevity-related genes. In this article we review these cloning techniques and discuss their advantages and limitations. Further research on the function of these genes as well as the network of their protein products will give better insight into the aging process as a whole and its associated pathologies.