Hormesis, a biologically beneficial response to low-dose exposure to stressors, has been reported to improve the functional ability of cells and organisms. Recent studies suggest that ancestral environmental conditions can influence the phenotypes of progeny. However, a key question of whether parents can transmit the beneficial memory of hormesis effects to their descendants remains largely unanswered. Here we show that hormesis effects induced in the parental generation can be passed on to the descendants in Caenorhabditis elegans. Animals subjected to various stressors during developmental stages exhibit increased resistance to oxidative stress and proteotoxicity. The increased resistance is transmitted to the subsequent generations grown under unstressed conditions. Remarkably, exposure of the male parents to these stressors also increases the stress resistance of the descendants and extends their lifespan. These findings suggest that the memory of hormesis effects can be transmitted to progeny through germline epigenetic alterations. Our analysis also shows that the insulin/ IGF-like signalling effector DAF-16 and the heat-shock factor HSF-1 in the parental somatic cells mediate the formation of epigenetic memory, and that the histone H3 lysine 4 trimethylase complex functions in the germline through generations to maintain the memory. Based on these results, we propose the germ-to-soma communications across generations as an essential framework for the transgenerational inheritance of acquired traits.