The theory corresponding to triple potential step chronoamperometry for a reversible charge transfer reaction in a static mercury drop electrode is presented. The equation for the current has been deduced assuming different diffusion coefficients for oxidized and reduced species and is valid when the reaction product is soluble in both the electrolytic solution and the electrode. The validity of equations proposed was verified by comparing theoretical i-t, double differential pulse and reverse differential pulse curves with those obtained experimentally for the system Cd2+/Cd(Hg). It can be concluded that the double differential pulse and reverse differential pulse techniques are more sensitive to the presence or absence of amalgamation than double pulse techniques.