A taste improving agent for food and beverage containing potassium chloride that can effectively relieve unpleasant tastes, such as bitter taste and harsh taste, attributed to potassium chloride without detriment to the flavor of the food and beverage; a process for producing a food and beverage containing potassium chloride of high palatability having the bitter taste and harsh taste of potassium chloride suppressed; and a food and beverage containing potassium chloride produced by the production process. Use is made of a taste improving agent comprising a basic amino acid and/or a basic peptide as an active ingredient. It is preferred that the basic amino acid be at least one member selected from among histidine, arginine and lysine and the basic peptide at least one member selected from among anserine, carnosine and balenine. This taste improving agent is added to a food and beverage containing potassium chloride, thereby obtaining a food and beverage containing potassium chloride with improved taste.