It is intended to provide a fermented beverage, especially a fermented beverage with beer taste, of high relish that is rich in isoamyl acetate. There is provided a process for producing a fermented beverage exhibiting excellent flavor, comprising carrying out alcohol fermentation of a water base mixture of water and a raw material containing a sugar ingredient optionally together with hop to thereby obtain a fermented beverage, wherein a corn protein decomposition product as a nitrogen source is added to the raw material before or during the alcohol fermentation.