Twenty-three gibberellins and their methyl esters were chromatographed by gradient reversed-phase C 18 partition and isocratic normal-phase silica adsorption high-perforamnce liquid chromatography (HPLC). These four complementary HPLC systems allowed for the necessary separation to resolve these gibberellins. The four HPLC systems can be used to identify radioactive metabolites in metabolism studies by co-chromatography of radioactive labelled gibberellins with authentic standards using UV and radioactive flow detectors. The highest separatio efficiency for these gibberellins was achieved with the reversed-phase C 18 HPLC of their methyl esters.