This study establishes a method, using different buffer conductivities and large-volume sample stacking (LVSS)-sweeping capillary electrophoresis, for analysis of carbamazepine (CBZ) and its five metabolites in serum. The capillary (50/60 cm) was filled with a high concentration of background electrolyte (150 mM phosphate, pH 3.5, containing 15 % methanol), followed by a large volume of samples (10 psi, 20 s) with low-concentration buffers (5 mM phosphate, pH 3.5, with 5 % methanol). When high voltage was applied (-20 kV), the sodium dodecyl sulfate (SDS) started to sweep the analytes to an outlet. Meanwhile, the analytes decelerated at the boundary between low- and high-conductivity buffers. Finally, a narrow sample zone was formed. The procedure of sweeping and separation was simultaneously carried out by a sweeping buffer (150 mM phosphate, pH 3.5) with 15% methanol and 50 mM SDS added, and the detection was performed by UV at 214 nm. The method was validated for linearity (r >/= 0.997), precision, and accuracy. The calibration curves were established for CBZ and its five metabolites between 0.03-25 and 0.03-3 μg/mL. The limits of detection (S/N = 3) were 0.01 μg/mL for each analyte. Compared with simple MEKC (0.5 psi, 5 s), this system can improve the sensitivity about 300-fold. Finally, this method was successfully applied to five patients, who had taken 200 mg CBZ daily, and CBZ levels were found to be from 3.72 to 5.82 μg/mL.