The Chromazurol s has been electropolymerized on the glassy carbon electrode and the Poly- Chromazurol s modified glassy carbon electrode (PCSMGCE) has shown excellent electrocatalytic activity toward the oxidation of ascorbic acid in phosphate buffer solution (pH=3). It was used for the simultaneous determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA). Analytical parameters were optimized and electrochemical behavior of modified electrode was studied. The calibration curves were obtained over the range of 3.0-2200.0 µmol Lâ1 AA, 0.09-980.0 µmol Lâ1 DA, and 0.05-900.0 µmol Lâ1 UA. Detection limits of 1.7 µmol Lâ1 AA, 0.05 µmol Lâ1 DA, and 0.03 µmol Lâ1 UA were obtained at pH 3.0. Prepared modified electrode had satisfactory results for determination of DA, AA and UA in dopamine injection solution, vitamin C tablets and human urine samples.