Sequence analysis of a rice BAC q3037(H0207F01) identified a cluster of five tandemly arranged peroxidase genes, osp1,osp2,osp3,osp4 and osp5, within a 22.5 kb region. osp4,osp5 each have three exons interrupted by two introns, while osp1,osp2 and osp3 each have two exons interrupted by a single intron. The five genes were predicted products of 338, 335, 336, 343 and 346 amino acid residues, respectively, including putative signal peptide sequence at the amino-termini. And OSP1, OSP4 and OSP5 were predicted to be anionic peroxidase, OSP2 and OSP3 are cationic. Comparative analysis and evolutionary analysis of the clustered genes and other peroxidase family members revealed that the gene cluster occurred by tandemly gene duplications(from osp5 to osp1) and that osp5,ap1 and prx7 were potential orthologies, and osp1-5, ap1 and prx7 constituted a novel evolutionary branch of class III peroxidases.