A theoretical description of the nonlinear impedance of a first-order electrode reaction has been presented. The dependencies of the charge transfer resistance and the Warburg impedance on the amplitude of the sinusoidal voltage perturbation have been determined. The amplitude analysis of the charge transfer resistance and the Warburg impedance enables determination by extrapolation of the charge transfer resistance and the Warburg impedance for the zero amplitude. Additionally, the amplitude analysis of the charge transfer resistance enables the determination of the global charge transfer coefficients of the cathodic and anodic processes. The amplitude analysis of the Warburg impedance allows determination of the diffusion coefficients of the Ox and Red forms.