Disclosed is a fermented whey preparation produced by carrying out high-temperature sterilization of an aqueous whey protein solution having a solid content of 11 to 35% by weight and a pH value adjusted to 6.5 to 8.0, then subjecting the aqueous whey protein solution to lactic acid fermentation, and homogenizing the resultant fermentation liquor as such. The fermented whey preparation has a fermentation-derived unique and good flavor and, at the same time, has a refreshed and invigorating flavor and further has a velvety texture. The fermented whey preparation is also excellent in thermal stability and safety.