Mitochondrial DNA restriction fragment length polymorphisms are convenient markers for identifying cytoplasmic variation among plants. We have collected 212 wild soybeans (Glycine soja Sieb. et Zucc) from all over Korea, and classified mitochondrial genome types based on hybridization patterns in DNA gel-blot analyses using two mitochondrial DNA clones, cox2 and atp6, as probes. Korean wild soybean was classified with eight-mtDNA types, and some of the mtDNAs showed geographical clines among the regions. The diversity index of the mtDNA was much higher in the western and southern regions than in the eastern and northern regions of Korea, respectively. Dissemination and distributive characteristics of wild soybeans in Korea were discussed.