A study was conducted on the conversion of starch in sweet potatoes to sugar by the amylolytic enzymes during baking. Sugars were extracted with ethanol from the raw and baked sweet potatoes at the temperature of 55∼57, 70∼75, and 90∼95℃. The individual sugars in the extracts was identified by thin-layer chromatography- and the individual sugar content was determined by high -performance liquid chromatographic analysis. Sugars identified from the raw and baked sweet potatoes at the temperature of 55∼57℃ are glucose, fructose, and sucrose. Sucrose, maltose, glucose, and fructose were identified is the baked sweet potatoes at tile temperature of 70∼75 and 90∼95℃. There was no significant increase in glucose, fructose and sucrose content during baking. Maltose was formed only above the gelatinization temperature.