A series of physically coated and/or chemically bonded silica gel, samples was characterized by means of nitrogen adsorption at 77 K in a relative pressure range from 10(-6) to 0.99. The LiChrospher Si-100 chromatographic silica gel was modified by using 4’-cyano-4-biphenyl[4-(4-pentenyloxy)]benzoate and 4-biphenyl[4-(4-pentenyloxy)]benzoate, whose contents in the samples varied from 8 to 46 wt %. Standard characterization methods were used to obtain the specific surface area (BET method), the micropore volume (t-plot), the total pore volume, and the pore size distribution (BJH method). Moreover, the surface properties of the samples were assessed from low-pressure adsorption data and the adsorption energy distributions were calculated using a procedure based on the regularization method. It was shown that nitrogen adsorption allows to changes to be monitored in the specific surface area, porous structure, and surface properties of the materials under study. Low-pressure measurements revealed that the coating procedure provided a quite uniform coverage of the organic molecules on the silica surface, but the uniformity of the coverage was inferior to that obtained by the chemical bonding. Moreover, the chemical bonding procedure did not lead to blocking of smaller pores as was the case in the coating procedure. The obtained results proved the usefulness of nitrogen adsorption measurements in characterization of new and/or modified porous materials.