Arbuscular mycorrhizal fungi were observed in Botrychium ternatum native in Korea. The partial small subunit(SSU) of ribosomal DNA gene from the fern roots was amplified with primers AM1/NS31. Nucleotides sequence analysis of the clones revealed that two fragments were close to Glomus proliferum and G. sinuosum. The other three DNA fragments were close to those of G. proliferum with the relatively low similarities($92{sim}95%$) and speculated to be originated from three different species of Glomus(GLA006, GLA016, and GLA032). Five different nucleotide sequences close to three AM fungal species were found in the roots of B. ternatum native in Korea.