Discrete Fourier transform (DFT) was used to deconvolute the distribution of penetrability coefficient (α o -distribution, equivalent to pore size distribution) from electrochemical impedance data of porous electrodes. The working equation is the Fredholm integral equation of the first kind to correlate macroscopic impedance data to a theoretical model describing microscopic signal with the α o -distribution. Simulated and experimental impedance data were tested. Noise observed at high frequencies in Fourier space was removed before inversely Fourier-transforming the α o -distribution from Fourier space to real space. The accuracy of α o -distributions deconvoluted by DFT depended on the number, frequency range and quality of impedance data. The examples in this work showed that fairly accurate α o -distributions could be obtained by DFT deconvolution. Most promising method was to use the α o -distribution obtained from DFT deconvolution as the first guess to shape the true α o -distribution. Then, accurate α o -distributions could be obtained by estimating parameters of the pre-assumed distributions by using complex nonlinear least square fitting.