From the de Levie's theory for a porous electrode, the impedance can be expressed in function of the cylindrical pore characteristics: the pore length, the pore radius and the number of pores, If the pores have a finite length, these parameters can be regressed from the experimental impedance diagrams. In the case of a semi-infinite pore length, only the product r(3/2)n can be obtained. In this paper, two practical examples of porous electrodes were presented: the corrosion of cast iron in drinking water and the electrodissolution of copper in 1 M hydrochloric acid solution. In each case, the pore parameters were assessed.