Platycodon grandiflorum is a long-lived herbaceous and one of the very important herbal medicine and foods. P. grandiflorum is called do-ra-ji in Korea. Inter-simple sequence repeats (ISSR) markers were performed in order to analyse the phenetic relationships of four accessions of P. grandiflorum. Wild groups had higher expected diversity, 0.164 for Korean and 0.157 for Chinese accessions than those of cultivated groups, 0.079 for Korea and 0.059 for China. The total genetic diversity in P. grandiflorum was 0.268 across species and the value was lower than average values for species with similar life history traits. The patchy distribution and domestication are proposed as possible factors contributing to low genetic diversity. An assessment of the proportion of diversity within species, HAccession/HSpecies, indicated that about 57.1% the total genetic diversity was among species. Thus, the majority of genetic variation (42.9%) resided within accessions. The estimated Nm (the number of migrants per generation) was very low among four accessions (mean Nm = 0.376). The low estimate of Nm indicated that gene flow was not extensive among four accessions. ISSR01-02 locus can be recognized as an unique locus of Korean groups (wild and cultivated accessions). Thus the locus can be used to distinguish Korean accessions from Chinese accessions. ISSR04-06 locus was found specific to Chinese groups (wild and cultivated accessions) and was not shown in Korean accessions. Although the size of sampling was not large enough for P. grandiflorum, the analyses of ISSRs will certainly provide an enhanced view on the phylogeny of accessions.