A repeated sequence with a length of 560 bp, termed as DH17, was obtained during PCR amplification of rice NBS-LRR homologues. A repeated unit of 352 bp in the DH17 fragment was revealed through sequence analysis and comparison, which has a high homology with the known sequences of OS48 and TrsA, and belongs to the same repeat family. Southern hybridization displayed that there are higher DH17 copies in the genome of an indica variety, ZYQ8,than that in the genome of japonica variety, JX17. The tandom repeated DH17 sequence was mapped on the long arm end of chromosome 12 through RFLP analysis of a double haploid population derived from ZYQ8 and JX17 using DH17 as a probe.