The article offers a general view of the graylings (Thymallidae) from the largest Siberian river basins, namely those of the Ob and Yenisei, including the Khantayskoye and Baikal Lakes. It provides data on some of the most important morphological features. It is shown that it is erroneous to consider the graylings only within the subspecies Thymallus arcticus arcticus. The reservoirs of the Altai-Sayan highlands, which drain to the north into the inland waters of Mongolia, should also be considered, as one of the two major centres of speciation and morphogenesis for graylings.