In the future circular economy all waste will be recycled into fuels, materials and active compounds. In particular, the food and agro-industries produce huge amounts of waste residues, which are actually underexploited and often polluting the environment. This book reviews the sources, extraction, processing and applications of value-added compounds from agro-waste, with a focus on drug delivery, tea, apple pomace, lignin nanocomposites, bioethanol, fertilizers and sitosterol. Food residues provide bioactive molecules, enzymes, vitamins, antioxidants, and animal feed.