The karyotypic and cytological characteristics of a native cyprinid fish of Iran Chondrostoma regium (Heckel, 1843) have been investigated by examining metaphase chromosomes spreads obtained from gill epithelial and kidney. The diploid chromosome number of this species was 2n=52. The karyotype consisted of 21 pairs of submetacentric and 5 pairs of subtelocentric chromosomes (12Sm, 5St). The arm number (NF) was 58. No heteromorphic sex chromosomes were cytologically detected. Chromosome number, karyotype formula and arm number of C. regium differentiate it from other closely related species. The results may be used for population studies, management and conservation programs.

The karyotypic and cytological characteristics of a native cyprinid fish of Iran Chondrostoma regium (Heckel, 1843) have been investigated by examining metaphase chromosomes spreads obtained from gill epithelial and kidney. The diploid chromosome number of this species was 2n=52. The karyotype consisted of 21 pairs of submetacentric and 5 pairs of subtelocentric chromosomes (12Sm, 5St). The arm number (NF) was 58. No heteromorphic sex chromosomes were cytologically detected. Chromosome number, karyotype formula and arm number of C. regium differentiate it from other closely related species. The results may be used for population studies, management and conservation programs.