The results of studies on the preparation of adsorbents with chemically bonded C-18 phases obtained by dynamic and static methods are presented. For characterization of the structure of the packings prepared, different physicochemical methods, especially high performance liquid chromatography (HPLC) technique, were used. Although adsorbents obtained by dynamic modification were characterized by a low cover density, the advantage of this method is the possibility of the preparation of columns with higher theoretical plate number and better resolution as well as regeneration of not fully used-up packings and chromatographic columns.