Collagen and elastin are extracellular matrix protein and their hydrolysates prepared form marine materials are used as functional food ingredients. The beneficial effects on human skin and joint conditions after oral ingestion have been reported. To elucidate the mechanisms for the beneficial effects, we attempted to detect the food-derived peptides in human blood after oral ingestion of the hydrolysate. Pro-Hyp and Pro-Gly were identified as major food-derived peptides in human blood after ingestion of collagen and elastin hydrolysate respectively. We have demonstrated that the bioactivities of those peptides on human skin fibroblast. Thus, it has been speculated that the food-derived peptides in human blood may play significant role in the beneficial effect after the ingestion of the hydrolysates. We also found the dose-dependent increase of food-derived collagen peptides in human blood that may causes individual differences on the beneficial effects. For effective utilization and value addition of marine products, it is important to understand the more detailed mechanism for the beneficial effects and potential bioactivity of marine food-derived peptides.