Objective To establish a method for determination of the concentration of creatin and creatinine in urine by high performance capillary electrophoresis (HPCE). Methods The determination was established by capillary micelle electrokinetic chromatography (MEKC). The electrophoresis buffer was the solution containing 20 mmol/L NaNa₂HPO₄-H₃PO₄4 supplemented with 100 mmol/L SDS with pH 5.50. An uncoated fused silica capillary with length of 53 cm and diameter of 75 m was used to separate the urine specimen which was 20fold dilution and imported with pressure of 1 psi for 4 seconds, then circulated for 15 minutes under voltage of 15 kV. The data were detected by diodearray detector (DAD) (λ=200 nm). Results The linear range of creatin was 4.9-2500 mol/L (r=0.9998) and creatinine was 4.9-2500 mol/L (r=1.0000). The recovery rate of creatin was 97.8%100.8% (mean of 99.2%), and that of creatin was 99.5%104% (mean of 101.8%). The coefficients of variation of interand intraassay for creatin and creatinine were 3.2% and 8.0%, and 2.3% and 6.8%, respectively. The detection limit of creatin was 1.4 mol/L and creatinine was 3.31 mol/L. Conclusion The established method in this study is less amount for applied sample, high precision and accuracy, wide range for linearity and low cost, and is suitable for routine clinical application.