Chromosome investigation of 19 Viola species from Korea was carried out. RAPD (Randomly Amplified Polymorphic DNA) analysis was also applied to examine the genetic variability among the species. The chromosome numbers in somatic cells were 2n=12 in V. orientalis, 2n=20 in V. collina and V. grypoceras, 2n=24 in V. acuminata, V. mandshurica, V. yedoensis, V. albida var. takahashi, V. albida, V. chaerophylloides, V. rosii, V. verecunda, V. vaiegata, V. keiskei, V. phalocrocarpa and V. hirtipes, 2n=44 in V. tricolor, 2b=48 in V. japonica, V. lactiflora, and 2n=72 in V. patrini, respectively. Ploidy levels were ranged from diploid (2x) to dodecaploid (12x), and tetraploid species were predominant with 66.7%. In Korean populations of all Viola species except artificial hybrid, V. tricolor, chromosome complements are composed of two kinds of genomes, x=6, x=10. The chromosomal evidence supports that V. orientalis belonged to the most primitive group. B-chromosomes were found in V. variegata. RAPD technique found to be useful and informative for detecting DNA polymorphism among Viola species. The species relationships by chromosomal data could be supported by the RAPD.