The separation and quantitation of coumarinic anticoagulant drug enantiomers were achieved by direct chiral capillary electrophoresis using complex maltooligosaccharide mixtures as stereoselective electrolyte modifiers. Chiral separations were characterized by a high selectivity and efficiency, enabling enantiomeric excess determinations. In addition, preliminary results indicate the applicability of the method for the determination of individual enantiomers in biological samples. So the method can be used to perform stereoselective pharmacokinetic studies.