Abstract: A method for the separation of warfarin enantiomers in serum by capillary electrophoresis was developed. The run buffer contained 140 mmol/L phosphate and 7 mmol /L methylated β-cyclo-dextrin(pH7.9), applied voltage 13kV, and detected at 210 nm. A baseline separation of two warfarin enantiomers can be obtained. The standard curve was linear from 0 to 5.0μg /ml and the limit ofdetection was 0.02μg/ml in serum. The precision and recovery rate was satisfying.