Analysis of 15 C-stained metaphase plates showed that all autosomes of Ochotona dauurica have the large pericentromeric heterochromatic blocks which were intensively stained. The 10-th and 15-th – 22-th pairs of autosomes have completely heterochromatic short arms. The last two small pairs of autosomes (23-th and 24-th) are composed of heterochromatin entirely. The large pericentromeric block of the X chromosome occupies 1/3 of the long arm. Heterochromatic structure of the Y chromosome was not confirmed . compared with published data.