Some bauxitic profiles, developed from alkaline rocks of the Poços de Caldas, Minas Gerais, Brazil complex were studied. The preliminary results show that nearly 40% of the total zirconium existing in the rock was leached out of the profile during the bauxitization process. On the other hand, it became evident that only a small part of the bauxitic residual zirconium is tied to zircon. Most of it is associated with the bauxitic ferruginous phase as colloidal hydroxides mixtures.