Seven autonomously replicating sequences (ARS) of rice were cloned by inserting random DNA fragments from the International Rice IR26 into the HindⅢ site of YIPS, which contained plasmid pBR322 and the yeast Ura3 gene. Recombinant DNAs were capable of transforming Ura-Saccharomyces cerevosiae 8534-8c at a high frequency which was qualitatively identical to that of pCH1 containing a yeast chromosomal ARS. With an exception (YIP5-ARS6), all of the Ura+ transformants grew slowly, were mitotically unstable under non-selective conditions and carried the transforming DNAs as autonomously replicating, superooiled circular molecules. When the ARS8 fragment was used as probe in a rice total DNA blotting experiment, a single hybrid band appeared and its size was identical to ARS8.