Disclosed are a method for producing a protein-containing acidic food and drink that comprises processing a protein emulsion having a pH value that is higher than the isoelectric point of the protein in the emulsion at a high temperature to make the emulsion having a pH value that is lower than the isoelectric point of the protein; the protein-containing acidic food and drink produced in the method; protein-containing acidic food and drink containing protein, fat and oil, and water-soluble polysaccharide, in which the particles dispersed have a mean particle size of not greater than 15 µm; and a protein-containing acidic drink containing protein, fat and oil, and water-soluble polysaccharide, in which the particles dispersed have a mean particle size of not greater than 15 µm and/or having a viscosity not greater than 20 centipoises (cPs). The protein-containing acidic food and drink is smooth, tasteful, palatable and has good storage stability.