This chapter deals with the ability of high-intensity ultrasound (HIU) processing to modify the structural and physicochemical properties of food proteins and how these changes affect their technological and biological functionality. The plausible mechanisms involved in the HIU-induced structure modifications of food proteins such as denaturation and/or aggregation processes, the use of HIU to promote protein glycation via the Maillard reaction, the capacity of HIU to modify food protein solubility, gelling, foaming, emulsifying properties or IgE immunoreactivity, and the effect of HIU on protein susceptibility to enzymatic hydrolysis are discussed in detail. Although more studies are necessary to broaden the knowledge of the effect of HIU technology on food protein conformation and functionality, HIU is an efficient technology that can modify the structure of food proteins and, consequently, modulate their functional properties.