In Japan, sweet potato is grown annually with the acreage of approximately 65,000 ha as of 1989. It is utilized mostly for starch production and table use through the market. Recent cultivars released from the breeding center have a wide range of utilizations not only in conventional use but also in food processing industry for high content of vitamins, low-amylase activity and extremely high starch content. Germplasm collections at the breeding center include Japanese old local cultivars, breeding lines and introductions from China, Fuji, Indonesia, New Zealand, Papua New Guinea, the Philippines, Solomon Islands and U.S.A. Total accessions of 1,200 were characterized and evaluated with their yielding abilities and degrees of resistance against pests and diseases. Wild relatives of sweet potato were also introduced from Latin America. The breeding program generally employs a usual crossing method, including combining ability tests. Biotechnology works have recently been initiated, aiming at improvement of breeding efficacy. Objectives of the breeding program are to raise productivity with a high starch content, pest and disease resistance, high quality for table use with better marketability and to develop new characteristics which facilitate greater utilization in food processing industry with a large scale.