A high-performance liquid chromatography tandem atmospheric pressure chemical ionization mass spectrometry method (HPLC-APCI-MS) has been developed for the characterization of astragalosides in the extracts of the roots of Astragalus spp. The [M - H](-) ions of astragalosides could be clearly observed in selected ion monitoring mode and APCI-MS-MS was used to further identify the structures of the astragalosides. Twelve astragalosides in the extracts of Radix Astragali obtained from Shandong in China were separated and identified. Using this method, astragalosides could be clearly identified and the profiles of these astragalosides could also be used to distinguish Astragalus spp. from different habitat regions. Copyright (c) 2007 John Wiley & Sons, Ltd.