Staple type sweet potatoes with little or no sweetness after cooking, and that appear to be suitable as everyday starchy foods, have been developed. The reducing and non-reducing sugar contents of these cultivars before and after microwave baking, and before and after storage, were compared with those of conventional sweet cultivars. The non-reducing sugar content is reduced slightly by baking in most cultivars. The reducing sugar content greatly increases with baking except in a few staple types. A series of varieties can be distinguished with respect to sugar changes. Storage at ambient temperature for 1 to 2 months results in slight increases in non-reducing sugar contents and little change in reducing sugars. Sugar contents before or after baking or storage are not related to dry matter, starch or protein contents. However, staple and sub staple cultivars are characterized by a drier mouthfeel.