To investigate the effect of differences in anthocyanin composition on radical- scavenging activity in the purple- fleshed sweet potato storage root, 124 sweet potato clones with compositions of anthocyanin were produced by crosses among superior sweet potato genetic resources, and were analyzed for anthocyanin composition and 1,1 – biphenyl -2 picrylhydrazyl (DPPH) radical- scavenging activity (RSA). The highest content of anthocyanin among the chones was twofold higher than the content of cv. Ayamurasaki, which has been released for use in industrial pigment production in Japan. The rang of variance in anthocyanin composition was very wide, as the ratio of peak areas of cyaniding-based anthocyanins to total anthocyanin peak area ranged from 85.7 to 6.0 The relationship between anthocyanin content and RSA was positively correlated. Correlation coefficients between RSA and the HPLC peak areas of cyaniding-based anthocyanins ranged from 0.606 to 0.687, whereas those of peonidin based anthoyanins were 0.124-0.271. results clearly demonstrated that cyaniding-based anthocyanins are closely related to DPPH RSA in sweet potato storage roots.