Аннотация:The paper presents the results of laboratory determination of the cation exchange capacity of the carbonate shale rocks of Domanic, Mendym and Sargai formations. It was found that the rocks of the Dominic formation are the inorganic ion-exhanger. The determined values of the cation exchange capacity vary in the well depth within 4.81÷7.57 meq/100 g for the Domanic formation, 3,71 meq/100 g for Mendym formation and 6,22 meq/100 g for the Sargai formation. It is shown that the obtained values of the cation exchange capacity integrally correspond to the composition of the rock clay fraction (especially hydromicas) of the analyzed samples. The correlation relations of the cation exchange capacity values with the amount of hydrocarbons and kerogen in the studied rock samples are not discernible.