As a part of the survey on the chemical compositions of Korean Sweet potatoes, the changes of chemical compositions of Suwon No. 118 and Suwon No. 147, which are representative varieties of sweet potatoes in Korea, were studied during storage. The result of the study showed the followings. 1. The moisture content of the both varieties were fairy uniform with higher value of Suwon No. 147 than another. 2. The starch content and crude starch yield in the stored root tuber were shown to be considerable uniform except decrease at the earlier part of storage and in January. 3. Reducing sugar content of them showed increase at earlier part, then almost uniform except gradual decrease in later part of the storage. 4. The content of total soluble sugar were gradually increased at the earlier part, then became almost uniform at the later part of the storage. 5. The sucrose content showed gradual increase except at the earlier part of the storage in which both varieties showed different feature in decrease of the content. 6. The content of crude protein and soluble protein were almost uniform throughout the storage.