Of the 20 arbitrarily chosen primers, six oligonucleotides decamer primers were used on the basis of the number of the polymorphisms generated in catfish (Silurus asotus) from Yesan and bullhead (Pseudobagrus fulvidraco) from Dangjin in Korea. Six primers were used generating a total of 602 scorable bands in catfish and 195 in bullhead population, respectively, ranging in size of DNA fragments from less than approximately 100 to larger than 2,000 base pairs (bp). Six primers yielded 199 polymorphic fragments (33.1%) in catfish and 47 (24%) in bullhead, respectively. In the present study, a total of 328 common fragments (an average of 54.7 per primer) were observed in catfish population, whereas 84 (an average of 14.0 per primer) in bullhead. The total number of specific fragments in catfish and bullhead population were 76 and 64, respectively. In catfish population, random decamer, OPA-17 (GACCGCTTGT) generated the highest number of fragments (a total of 141) in comparison with other primers used, with an average of 11.8. The common bands in the molecular weight of 300 bp generated by random primer OPA-06 (GGTCCCTGAC) were present in every individuals in bullhead population. The major polymorphic bands in the molecular weight of 100 bp generated by OPA-17 were identified in lane 14, 15, 17, 18, 19 20 and 21, which were identifying species in bullhead population. The average bandsharing values (BS values) of all of the samples within catfish population ranged from 0.575 to 0.945, whereas 0.063-1.000 within bullhead population. The bandsharing value (index of similarity between individuals) between individual No. 5 and No. 9 showed the highest level within catfish population, whereas the bandsharing value between individual No. 1 and No. 2 showed the lowest level. The single linkage cluster analysis resulted from four primers, indicating four genetic groupings composed of group 1 (C1-C10, all of the catfish samples), group 2 (B11, B12, B13, B14, B16, B17, B18, B19), group 3 (B15) and group 4 (B20 and B21). The dendrogram reveals close relationships between individual identities within two species populations and individuals derived from the same ancestor, respectively. However, genetic distances between two species populations ranged from 0.124 to 0.333. The shortest genetic distance (0.042) displaying significant molecular differences was between individual No. 6 and No. 9 catfish population. The shortest genetic distance (0.033) displaying significant molecular differences also was between individual No. 18 and No. 19 in bullhead population. Reversely, the genetic distance of individual No. 20/21 among individuals in bullhead population was highest (0.333). This result showed that bullhead No. 20 and 21 were distinct from other individuals within bullhead population.