In this work, mixtures Zn-TiO2 (anatase) in molar ratio 1:1 were mechanochemically activated in air atmosphere, and submitted to thermal treatments in order to study its thermal transformations. The behavior of the system during the milling was followed by X-ray diffraction (XRD), differential thermal analyses (DTA) and thermogravimetric analyses (TGA). Mechanochemical activation produces a progressive loss in crystallinity of the starting powders, with simultaneous oxidation of metallic Zn. However, the formation of neither ZnTiO3 nor Zn2TiO4 could be detected. At temperatures above 600degreesC, the thermal treatments resulted in the formation of ZnTiO3 and Zn2TiO4, at lower temperatures and shorter holding times for samples activated during longer times. The non-activated mixture exhibited a very different behavior, yielding Zn2Ti3O8 and Zn2TiO4 without evidence of ZnTiO3 formation. The obtained results are explained on the basis of reaction mechanisms taking place in the activated and non-activated samples. (C) 2004 Kluwer Academic Publishers.