The separation of methylenedioxyamphetamine-related designer drugs by capillary zone electrophoresis (CZE) and on-line detection with ionspray mass spectrometry (CZE-MS) is described. CZE-MS coupling permits the fast and reliable identification of this class of substances in the femtomole range. As methylenedioxyamphetamines have an asymmetric carbon atom, several cyclodextrins were investigated as buffer additives for the chiral separation of these compounds.