Nanocrystalline magnesium oxide with high surface area has been synthesized by precipitation method using ammonium hydroxide and polyvinyl alcohol as precipitant and polymeric surfactant, respectively. The results show that the polymeric surfactant (PVA) has a significant effect on the synthesis of MgO nanocrystals. The specific surface area of the MgO powder decreases from 123 m(2)g(-1) to 61 m(2)g(-1) and the crystallite size on the (200) plane increases from 12.2 nm to 14.2 nm with increasing temperature from 600 degrees C to 800 degrees C. Transmission electron microscopy (TEM) and N-2 adsorption/desorption isotherm also show a nanostructure consisting of aggregates or agglomerates of particles forming slit shaped pores (plates or edged particles like cubes). (C) 2009 Elsevier B.V. All rights reserved.