Magnesium oxide particles with a new morphology of stacks of plates have been prepared through a precursor method. Magnesium oxalate dihydrate, prepared by the reaction of an aqueous concentrated solution of magnesium chloride with macro-crystalline magnesium oxide followed by ammonium oxalate treatment, was used as the precursor. The magnesium oxide particles with the morphology of stacks of plates were obtained by calcination of the magnesium oxalate dihydrate at 500°C for 3h. The products were characterized by an array of analytical techniques. The morphology of prepared MgO is different from other known morphologies of magnesium oxide.