In the present investigation, the nano- and micro-sized powders were synthesized by stoichiometric contents of magnesium and aluminum nitrates using combustion-oxidation method. The study was conducted over a wide range of operating conditions, in terms of fuel ratio and calcination temperature. The characteristics of magnesium aluminate powders were studied by differential thermal analysis and thermogravimetry (DTA-TG), Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), and transmission electron microscopy (TEM) techniques. The thermal stability of powders was evaluated by calcination at different temperatures. Differences of the specific surface areas were related to the composition and crystallite size. The importance of fuel ratio and calcination temperature to achieve the nano- and micro-sized oxide was discussed in detail. The fuel ratio of 0.56 and calcination at 800 ℃ provided the conditions to achieve the nano-scale magnesium aluminate powders, smaller than 20 nm. The application of presented algorithm can be an important tool for control of particle size in the nano- and micro-scale.