In this article a potentiometric method for reducing sugar quantification is described. Copper(II) ion reacts with the reducing sugar (glucose, fructose, and others), and the excess is quantified using a copper wire indicator electrode. In order to accelerate the kinetics of the reaction, working conditions such as pH and temperature must be adjusted. However, a good relationship of mass of reducing sugar to potential was reached. Some of the advantages of the method are its simplicity, low cost, and that can be carried out even in colored and turbid samples. The analysis is safer than the standard Lane-Eynon method for determination of reducing sugars. To our knowledge, the use of a simple copper wire as electrode has not been reported previously for this type of determination, leading to a simplification of the experimental equipment. (Contains 2 figures and 1 table.)