The study deals with the use of attapulgite as a corrosion inhibitor of two metals, namely aluminum and zinc, and their alloy (aluzinc), in a 0.5 M hydrochloric acid medium. The study was carried out by monitoring the free-corrosion potential and performing dynamic polarization measurements (Tafel curves) at different concentrations of inhibitor in solution. The measurements suggested that in a 0.5 M acidic medium, the surface of each of the three materials was attacked. The decrease in current density was very noticeable in aluminum and zinc at a level of 2 g×L-1. A weak tendency to passivity was noticed for zinc and aluzinc. The experimental results obtained showed a decrease in the current intensity in the presence of the corrosion inhibitor in the acidic medium. The maximum inhibitory efficiency rate reached for the metals and their alloy was higher than 99 %. This percentage was obtained for aluminum and zinc in the presence of 4 g×L-1 of attapulgite and 3 g×L-1 for aluzinc.