Physical properties and internal structure of five starches isolated from two types of sweet potato varieties ( Shui-lin Tainung NO. 57, SL57;Shui-lin Tainung NO. 66, SL66;Da-du Tainung NO. 57, DD57;Da-du Tainung NO. 66, DD66 and Jin-san Tainung NO. 66, JS66 ) were characterized and compared with tapioca starch. The shapes of sweet potato starch granules were spherical, bell-like and polygonal, and no growth ring was observed. All sweet potato starches used in this study exhibited typical A type crystalline pattern. Phosphorus content and granule size distribution of sweet potato starch ( SPS ) ranged from 46 - 48 ppm and 2 – 40