A surfactant assisted precipitation method was employed for the preparation of nanocrystalline magnesium oxide with high specific surface area and plate-like shape. Ammonium hydroxide and polyvinyl alcohol (PVA) were used as precipitant and polymeric surfactant, respectively. The effects of several process parameters such as refluxing time, refluxing temperature and magnesium oxide to PVA monomer unit mole ratio (MgO/PVA) were investigated on the structural properties of the powders. The obtained results showed that the increase in refluxing time and temperature increased the specific surface area and decreased the crystallite size. The results revealed that the polymeric surfactant (PVA) has a significant effect on the synthesis of MgO nanocrystals and led to obtain a powder with higher surface area and plate-like shape. (C) 2009 Elsevier B.V. All rights reserved.