To develop an efficient gene isolation method for rice we introduced the maize Ac/Ds system into rice. Extensive analysis of their behavior in rice for several generations indicated that Ac and Ds in the presence of Ac transposase gene actively transpose in rice. A wide spectrum of mutations affecting growth, morphogenesis, flowering time and disease resistance have been obtained in the population carrying Ac/Ds and some of them were genetically analyzed. Main efforts are currently being made to isolate genes responsible these mutations. In addition, a number of Ac/Ds were mapped on chromosomes and mapped elements will be used in the future for directed tagging of genes with known chromosomal positions.