Detailed karyotypes analyses were carried out in 30 populations of Korean L. maximowiczii Regel. The populations were constituted with 43 diploids (2n=2x=24) and 38 triploids (2n=3x=36). The lengths of mitotic metaphase chromosomes ranged from 13.22 µm to 25.18 µm, with a total length of 203.78 µm in diploid plants. In triploid plants, the chromosome lengths ranged from 14.28 µm to 27.75 µm, with a total length of 214.42 µm. There was only one cytotype identified by karyotype analysis in both diploid and triploid populations. The basic set of somatic chromosome complement consists of two metacentrics (chromosomes a and b), two subtelocentrics (chromosomes c and d), and eight telocentrics (chromosomes e, f, g, h, i, j, k, and l) in both diploid and triploid populations. Four loci of 45S rRNA genes were observed by FISH, and three of the four loci correspond to the secondary constrictions. One additional 45S rRNA locus was observed by FISH at the near telomere of the long arm of a set of telocentric chromosomes. There were two 5S rRNA gene loci, which were closely placed on the long arm of a set of subtelocentric chromosomes that were not the 45S rRNA loci-carrying chromosomes. In conclusion, the karyotypes in both diploid and triploid popu- lations were identical, implying that the triploid organisms are autotriploids.