This chapter describes the most promising food byproducts for the cosmetic industry, particularly focusing on their composition and skin effects. The re-use of bioactive compounds from food waste as cosmetic ingredients needs the knowledge of basic skin structure and absorption mechanisms. Skin has three major regions: epidermis, dermis and hypodermis. Food by-products are particularly rich in antioxidants. The antioxidant activity is an excellent example of a functional benefit that extracts from food by-products can deliver to the skin. Cosmetic treatment of the current generation against wrinkles relies on the antioxidant properties of some ingredients. Food waste is nowadays considered a matter of treatment, minimization and prevention due to the environmental effects induced by their disposal. According to the Food and Agriculture Organization, one-third of the edible part of food produced for human consumption is lost or wasted globally.