Two simplified methods are proposed for determining the internal ionic resistance of a porous electrode using linear voltammetry in the double layer region. With the 70% current response time t 0.7 on linear voltammogram and the independently measured uncompensated solution resistance R e, the internal ionic resistance of a porous electrode can be calculated using the equation R p=2.483t 0.7/C total−2.989R e, where C total is the total capacitance of the porous electrode and can be deduced from the plateau current on the voltammogram. When R p is not much smaller than R e, it is also possible to estimate the ionic resistance according to the curve shape of the linear voltammogram without knowing R e.