Karyological properties of Cyprinus carpio, Capoeta damascina, Luciobarbus pectoralis, Pseudophoxinus zekayi, Squalius seyhanensis and Alburnus adanensis from the Seyhan and Ceyhan river systems were investigated by examining metaphase chromosomes through Giemsa staining, C-banding and Ag-NOR techniques. The diploid number of chromosomes in A. adanensis, P. zekayi and S. seyhanensis were 50, in C. carpio and L. pectoralis 100, and in C. damascina 150. Sex chromosomes were not observed in any of the examined species. Several chromosomes presented C-bands in pericentromeric and/or paracentromeric position, near the centromere. Some species had centromeric and pericentromeric heterochromatic blocks. NORs were observed in one pair of submetacentric chromosomes in L. pectoralis, P. zekayi, S. seyhanensis and A. adanensis, in one pair of metacentric chromosomes in C. carpio and three pairs of chromosomes in C. damascina. The cytogenetic features of endemic fishes A. adanensis, L. pectoralis, P. zekayi and S. seyhanensis were detected for the first time in this study.