A modified carbon paste electrode with SiO2/SnO2/Phosphate/Meldol a's blue, SSPMelB, was used to study the electrocatalytic oxidation of ascorbic acid by cyclic vottammetry and chronoamperometry. The adsorbed dye mediates ascorbic acid oxidation at an anodic potential of 0.04 V vs. saturated calomel electrode (SCE) at pH 7.0, in 0.5 mol L-1 solution. The linear range of the sensor is between 4.0 x 10(-7) and 2.0 x 10(-3) mol L-1, with a limit of detection of 4.0 x 10(-7) mol L-1. This novel electrode shows good analytical performance for determination of ascorbic acid in medicine and commercial fruit juice.