Production and post-production processes in meat, dairy, and fish industries produce large quantities of waste and different by-products. These materials are generally discarded without any significant utilization by humans. Meat industry waste products such as liver, kidney, heart, stomach, tongue, blood, bone, etc., are rich in nutrition required for humans (as diet), animals (as feed), and soil (as fertilizer). In the dairy industry, whey (cheese), skim milk (cream), ghee residue (ghee), buttermilk (Chhach), etc., are the by-products of production line. All these by-products are composed of high nutritional components such as proteins, unsaturated fats, minerals, bioactive peptides, etc. Fishery industry waste is rich in collagen and omega-3 fatty acid content. These precious wastes need to be utilized without exposing them directly to the surroundings. Without processing, the high content of insoluble organic (blood compositions, wastewater, etc.) waste items also acts as an environmental hazard. High rate of mineral deposition in soil causes toxicity effects on human, plant, and marine ecology. So this chapter is focused on nutritional values and processing of the waste material for decreasing waste and converting waste to wealth.