The karyotype of Clarias gariepinus was described by means of G-banding, C-banding, Q-banding, and Ag-NORs (NORs) staining in this study. Samples were collected from 2 regions of Turkey: the Goksu Delta and Orontes River. Although samples from both regions had the same diploid chromosome number and fundamental arm number, (2n = 56, FN = 100), they had remarkable differences in karyotype formula and distribution of rDNA sites, according to silver nitrate staining and G-banding. While the karyotype formula for Orontes River samples was 24m + 10sm + 10st + 12a, the Goksu Delta samples' was 28m + 6sm + 10st + 12a. Comparative analysis showed that there was intraspecific variability in NORs and different NOR numbers in the 2 populations. The study's findings show that the Goksu Delta and Orontes River samples differed from each other.