N2 adsorption isotherms at ca. 77 K on macroporous α-Al2O3 have been measured and analyzed in the frameworks of the classic thermodynamic approach, with independent experimental data obtained by means of SEM-EDX, XRD, TGA, helium pycnometry, and mercury porosimetry taken into account. It is shown, that presence of adsorbed water considerably influences N2 adsorption, which gradually increases with temperature of the degas treatment. Simultaneously, the shape of the isotherms has a trend to change from Type II to Type VI, that assumes changing of adsorption mechanism from progressive increasing of the adsorbed layer thickness towards layer-by-layer adsorption. Corrected and smoothed isotherms are presented in the tabular form as reference for subsequent more comprehensive analysis using molecular statistical approaches.