The study focuses on regeneration and reuse of in-house synthesized MgO nanocrystallites used as an adsorbent for the removal of Acid Orange 7 dye from wastewater. The dye-adsorbed MgO were regenerated by two major steps: drying and combustion. The used MgO were dried at room temperature of 35 degrees C +/- 5 degrees C, at an optimized time of 8-10 h time and the dried MgO were combusted at an optimized temperature of 500 degrees C in muffle furnace for 25 min. The regeneration and reuse of MgO could be effectively carried out for five adsorption-combustion cycles. In every cycle of regeneration, 8-10% by weight of MgO was lost. The X-ray diffraction analysis showed the phase purity and the calculated crystallite size of synthesized, first, second, third, fourth and fifth regenerated MgO were noted as 21.67, 21.67, 21.67, 24.74, 24.74 and 24.74 nm, respectively. The scanning electron microscopy analysis showed that agglomeration of regenerated MgO particles increased with the increase in number of adsorption-combustion cycles.