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Textural properties of homoionic Na- and Ca-bentonite (MX-80 from Wyoming) were studied by nitrogen adsorption. Bulk samples, which contained 20% of nonclay minerals and purified samples, were taken for the study. Powder samples and compressed pellets, which were prepared by applying a uniaxial stress of 57 MPa, were examined. Presence of nonclay minerals in the bulk samples affects significantly textural properties of the system. In particular, nonclay minerals prevented full compression of the bulk samples. In comparison to Na-saturated purified samples, higher values of surface area and total pore volume were detected in Ca-saturated samples. In addition, amount of the trapped pores was considerably higher in Ca-saturated samples than that in Na-saturated ones. In Ca-saturated samples, values of micropore surface area and micropore volume were very low, or even equal to zero. In Na-saturated …