Lifespan is regulated by a complex combination of environmental and genetic factors. Autophagy, which is a bulk degradation system of macromolecules and organelles, has an important role in various biological events. InCaenorhabditis elegans, several autophagy genes have been shown to have a role in promoting longevity, but many other autophagy genes have not been examined for their role in the lifespan regulation. Here we have systematically examined the effect of RNAi suppression of 14 autophagy genes on lifespan. While maternal RNAi of autophagy genes in wild-type worms tended to reduce lifespan, maternal RNAi of each of seven autophagy genes in the insulin/IGF-1 receptordaf-2mutants extended lifespan. Remarkably, RNAi ofunc-51/atg-1,bec-1/atg-6oratg-9, from young adult, i.e. after development, extended lifespan in both wild-type animals anddaf-2mutants, although RNAi of one or two genes shortened it. Moreover, our analysis suggests that the lifespan extension, which is induced by RNAi ofunc-51,bec-1oratg-9after development, does not require the transcription factordaf-16, the NAD+-dependent protein deacetylasesir-2.1or the genes related to mitochondrial functions. Collectively, our results suggest that autophagy may not always be beneficial to longevity, but may also function to restrict lifespan inC. elegans.