Karyotypic analysis and FISH (fluorescence in situ hybridization) with 45S and 5S rRNA genes were carried out in Persicaria tinctoria H Gross. The somatic metaphase chromosomes were ranged from 2.25 ${mu}m$ to 1.50 ${mu}m$ in length. Chromosome number was 2n = 4x = 40 with the basic number of x = 10. The chromosome complement of the species consisted of 16 pairs of metacentrics (chromososomes 1,2,3,4,6,7,8,9, 10, 11, 12, 13, 15, 18, 19 and 20) and 4 pairs of submetacentrics (chromosome 5, 14, 16 and 17). The karyotype formula was K(2n) = 4x = 32 m + 8 sm. In FISH analysis, three pairs of 45S rRNA gene loci on the terminal region of submetacentrics (chromosomes 5, 16 and 17) and two pairs of 5S rRNA gene loci on the centromeric region of metacentrics (chromosomes 9 and 11) were detected, respectively.