A method has been developed for the quantitation of the antiepileptic drug vigabatrin (VGB) in human plasma. It is based on CE with LIF detection. The effect of the pH of the buffer and of N-methylglucamine (GLC) as BGE constituent was investigated. The final BGE consisted of 50 mM borate buffer, pH 9.0, with 100 mM GLC and enabled separation within 12 min at 20 W voltage. An SPE procedure was used for the pretreatment of biological samples, based on mixed-mode lipophilic-cation exchange cartridges, followed by a derivatization step with 6-carboxyfluorescein-N-succinimidyI ester (CFSE). Fluorescence was excited by an Anion laser (lambda(exc) = 488 nm). Linearity was observed in the 10-120 mu g/mL plasma concentration range. Extraction yield was > 96%, precision (expressed as RSD) < 6.7% and accuracy (recovery) was between 97.0 and 101.6%. The method has been successfully applied to the analysis of VGB in plasma of epileptic patients undergoing therapy with the drug.