A simple micellar capillary electrokinetic chromatography (MEKC) with UV detection is described for analysis of cefepime in plasma and cerebrospinal fluid by direct injection without any sample pretreatment. The separation of cefepime from biological matrix was performed at 25degreesC using a background electrolyte consisting of tris(hydroxymethyl)aminomethane (Tris) buffer with sodium dodecyl sulfate (SDS) as the electrolyte solution. Under optimal MEKC condition, good separation with high efficiency and short analyses time is achieved. Several parameters affecting the separation of the drug were studied, including the pH and concentrations of the Tris buffer and SIDS. Using cefazolin as an internal standard, the linear ranges of the method for the determination of cefepime in plasma and cerebrospinal fluid were 1-50 and 1-20 mug/mL, respectively; the detection limits of plasma (signal-to-noise ratio = 3; injection, 5 kv, 5 s) and cerebrospinal fluid (signal-to-noise ratio = 3; injection, 0.5 psi, 3 s) were 0.2 mug/mL and 0.3 mug/mL, respectively. Application of the proposed method for determination of cefepime in plasma and cerebrospinal fluid collected after intravenous administration of 2 g cefepime in patients with meningitis was demonstrated.