Advances in protein co-precipitation technology over the past two decades have made it possible to commercially produce different types of proteins from mixtures of raw materials. Incorporation of protein co-precipitates improves the functional (e.g. appearance, texture, and stability) and nutritional characteristics of many food products. Increasing world population, increasing demand for and cost of protein-rich foods, and the continuing need to improve the nutritional and functional properties of protein ingredients have contributed to greater research into blends or composites as food ingredients. Protein co-precipitates have a range of biological, physical, chemical, functional, sensory and nutritional properties giving the potential application as ingredients in the food industry, though relatively little published information is available on this subject. There is limited information about the use of protein co-precipitates by the food industry when developing products for different groups of potential consumers. The aim of this review is to evaluate the current status of protein co-precipitate research as a potential way of improving utilization of protein rich raw materials (e.g. dairy protein), oil seed meals (e.g. sesame, soybean, flaxseed and canola) and by-products (e.g. brewing yeast). By blending proteins from different sources, protein co-precipitates are a way of overcoming deficiencies in essential amino acid contents found in proteins from a single source, which giving ingredients with good functional properties and desirable sensory characteristics.