<jats:title>Abstract</jats:title><jats:p>A sensitive, high performance ion‐exchange chromatographic method has been developed for the determination of castanospermine, 1‐deoxynojirimycin, 1‐deoxymannojirimycin and swainsonine. This series of sugar‐shaped alkaloids of plant and microbial origin are potent glycosidase inhibitors. The procedure presented demonstrates their separation on a cation exchange column under isocratic conditions and, following post column addition of 300 Mm sodium hydroxide, detection by pulsed amperometry. The procedure employed a Dionex guard column CG3 with a CS3 separator column and a mobile phase which consisted of 10 Mm hydrocholoric acid.<jats:p>Linear calibration curves for the analysis of these alkaloids have been shown to extend over 2 decades from 10 ng/mL to 20 μg/mL. The method has been compared to previously reported enzymatic assays for the alkaloids. The identity of certain chromatographic peaks has been confirmed by enzyme inhibition studies.<jats:p>The method has been applied to the measurement of natural, low levels of castanospermine found in plant tissues.