A karyotypic analysis was carried out on the Russian sturgeon using C‐ and Ag‐NOR banding techniques and base specific DNA‐binding fluorochromes. The standard karyotype is 2n = 258±4. Nucleolar organizer regions are localized on each of the telomers of four metacentric chromosomes, and on one telomer of four metacentric, four acrocentric, and one large metacentric. C‐bands are mainly located at the centromeric regions of the acrocentric chromosomes. The biarmed chromosomes exhibit either weak or absent C‐bands, but four metacentrics are completely heterochromatic. By means of double staining with complementary fluorochromes, chromomycin A3and DAPI, a pattern of fluorescent regions is recognizable. Interspersion of the opposite DNA base pairs along the chromosomes is discussed.