The uricase inhibitors urate, xanthine, oxonate and cyanurate were tried as ligands, for preparing bioaffinity support for chromatographic separation of uricase. Only derivatised purines showed inhibitory properties, whereas derivatised s-triazines seemed to lose their absorptive capacity. Chromatographic separation on a bioaffinity support produced higher yield and better purification of uricase than conventional chromatographic technique.