By means of the rotating disk‐ring electrode technique, the mechanism of the anodic dissolution of indium at a disk in at current densities to above 10 ma/cm2 has been determined to be a rapid one‐electron reaction to an In(I) species sufficiently stable to be detected in theoretical amount at the ring. The Tafel behavior of the disk reaction and the anodic and cathodic ring collection efficiencies are in accord with the above; the ring current‐potential curves further show that the slowness of the In(I)‐In(III) reaction permits the thermodynamically less‐favored state to be formed in quantity. Anodic dissolution of indium from amalgams is placed on a consistent basis by a quantitative treatment which takes into account the variable metal activity.