The selection of a reversed-phase liquid chromatographic (RP-LC) column with suitable selectivity for a particular separation is difficult if the brand name of the column is not known. The monographs of the European Pharmacopoeia and other official compendia for drug analysis only give a general description of the stationary phase to be used in the operating procedure of a liquid chromatographic method. A project to develop a chromatographic test procedure to characterise RP-LC C-18 columns was started earlier and resulted in a fast, simple, repeatable and reproducible test procedure. Four column parameters, determined on 69 RP-LC C18 columns, allowed the characterisation and ranking of these columns. In this paper. an overview of this column classification system is given with an application on the separation of vancomycin and some of its impurities. It is shown that the column ranking system is a helpful tool in the selection of a suitable column. (c) 2006 Elsevier B.V. All rights reserved.