Genus Spiraea is a long lived woody species that is primarily distributed throughout Asia and Europe. We evaluated a representative sample of the fourteen taxa in Korea with nuclear ribosomal DNA internal transcribed spacer sequences (ITS) to estimate genetic relationships within genus. The molecular data allowed us to resolve well-Supported clades in taxa. Aligned nucleotide sequences of the length of ITS1 were nearly constant within genus Spiraea varying from 237 to 238. However, S. pubescens and S. salicifolia were showed 227 bp and 242 bp, respectively. Especially, the 5.8S subunit of all taxa of Spiraea was found to 157-165 bp nucleotides. However, aligned nucleotide sequences of the length of ITS2 vary from 263 to 271 bp. Total alignment length is 670 positions, of which 65 are parsimony-informative, 45 variable but parsimony-uninformative, and 410 constant characters. The phylogenic tree showed Korean taxa of genus Spiraea were well separated each other. S. prunifolia for. simpliciflora and S. blumei are conform one group and S. chartacea is the sister to them. S. fritschiana and S. S. miyabei are conform one group and S. japonica is the sister to them. S. pubescens was recognized as a distinct species.