Aging is a process of gradual functional decline accompanied with increased mortality rate. Using model organisms, researchers have demonstrated that aging is modulated by highly conserved signaling pathways, and genetic or environmental modulations can lead to significantly extended life span and delayed functional decline. Many exciting discoveries on the molecular mechanisms of aging were initially made in C. elegans, which is a great system for biology research because of the ease of genetic analysis and the conservation with higher species. Here we review the progress in aging research using C. elegans as a model. We focus on the highly conserved insulin/insulin-like growth factor 1 signaling (IIS) and target of rapamycin (TOR) pathway, as well as prospects for future studies.