A novel modified glassy carbon electrode (GCE) with a binuclear copper complex was fabricated using a cyclic voltammetric method in phosphate buffer solution. This modified electrode shows very efficient electrocatalytic activity for anodic oxidation of both dopamine (DA) and ascorbic acid (AA) via substantial decrease in anodic overpotentials for both compounds. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) using this modified electrode show two well-resolved anodic waves for the oxidation of DA and AA in mixed solution, which makes it possible for simultaneous determination of both compounds. Linear analytical curves were obtained in the ranges 2.0-120.0 mu M and 5.0-160.0 mu M for DA and AA concentrations by using DPV methods, respectively. The detection limits were 1.4 x 10(-6) M of DA and 2.8 x 10(-6) M of AA. This electrode was used for AA and DA determinations in medicine and foodstuff samples with satisfactory results.