Water effect on the combustion preparation of MgO is presented. The obtained materials are characterized through their specific surface area, morphology, particle shape, fractal dimension and Co2+ sorption. The surface fractal dimension of the combustion prepared sample was 2.0 but in those where water was included it decreased to 1.8. In the sample prepared by calcination it was 2.3. A linear correlation between the fractal dimension and Co2+ sorption was found. (C) 2008 Elsevier B.V. All rights reserved.