The effect of immersion time, temperature, concentration, and an applied external current on the dissolution of commercially pure aluminum in sodium hydroxide solutions is described. A technique resulting in reproducible dissolution rates is given. The instantaneous rate of dissolution increases at a decreasing rate with immersion‐time and is directly proportional to the weight‐loss and inversely proportional to the immersion‐time. The effect of temperature on the rate of dissolution is given by the Arrhenius equation. It is shown that the changing rate and electrode potential are determined by the precipitate which forms local cathodes on the surface of the metal during dissolution. The electrode potential varies as the rate of dissolution, a measure of the local cell current, varies.