Cr-pillared smectites by intercalation of OH-Cr species in montmorillonite, beidellite, nontronite and saponite smectite clays followed by heating at 450 o C in air or nitrogen atmosphere were prepared. The pillaring reagent containing OH-Cr species was obtained from chromium nitrate solutions by adding NaOH with OH/Cr=2 and hydrolyzed at 60 o C for one day. The samples were characterized by X-ray diffraction, by N 2 adsorption-desorption isotherms, by acidity measurement and by chemical analysis. The Cr pillared smectites prepared at 450 o C in nitrogen atmosphere showed interlayer spacing in the range of 13.8-18.8 Å. These values were a function of the type of smectite members. The micropore surface area, the micropore volume and the d(001) spacing after pillaring of different smectite members increased with the amount of chromium retentions. Cr-PILCs (pillared interlayered clays, PILC) showed Lewis (L) and Bronsted (B) acidity characteristics and the L/(L+B) ratio was higher in Cr-PILCs prepared from smectites with higher tetrahedral negative charge of the structure. The charges and the composition of the smectite structures influenced considerably the properties of the Cr-PILCs.