Abstract A rapid and accurate capillary zone electrophoresis (CZE) method is described for simultaneous determination of cefepime and L‐arginine in cefepime for injection. Best results were achieved with the background electrolyte (BGE) prepared by titrating 40 mM sodium dihydrogen phosphate with phosphoric acid to pH 2.3 and an applied voltage of 30 kV in a bare fused‐silica capillary. The capillary temperature was 30°C and detection was made at 195 nm. L‐Histidine was used as internal standard (IS) to ensure acceptable precision. Separation was completed in less than 12 min. The optimized method was validated for selectivity, linearity, accuracy, precision, ruggedness, repeatability, and detection limits. The linear range for cefepime and L‐arginine was 57–571 and 39–394 µg mL−1, respectively. Limit of quantitation (LOQ) was 6 µg mL−1 for cefepime and 3 µg mL−1 for L‐arginine. Relative standard deviation (RSD) for peak area ratio (PAR, the area of analyte peak, divided by the area of the IS peak) was less than 1.0%.