Sequences from the internal transcribed spacer (ITS) regions of nuclear ribosomal DNA were determined to assess their potential as a phylogenetic tool for Korean Acer species, including A. okamotoannum and A. takesimense which are endemic on Ullung Island of volcanic origin. Although the genus Acer has been studied by various authors, different infrageneric dispositions have been suggested, and the phylogeny of the genus has been in dispute. The variation of ITS sequences from seven species of Acer was very low among species within the same section, but comparative analysesof the molecular data obtained suggest that ITS sequences may provide enough phylogenetic resolution for sectional relationships in the genus.