Adriamycin and daunorubicin and their metabolites adriamycinol and daunorubicinol were separated by reversed-phase liquid chromatography using LiChrosorb RP-2, RP-8 and RP-18 as supports and acetone, acetonitrile and alcohols as organic modifiers in the mobile phase. The highest separation selectivity was obtained using a mobile phase containing low concentrations (less than 20%) of acetonitrile. The length of the hydrocarbon chains of the surface-modified silica supports had no significant influence on the selectivity. The lowest capacity factor was obtained with 40-60% of organic solvent in the mobile phase. Increasing the length of the hydrocarbon chains of the supports increased the retention of the solutes.