A process coupling membrane electrolysis and electrodialysis is implemented to treat ammonium nitrate wastewater. Membrane electrolysis produces ammonia and nitric acid while electrodialysis reconcentrates the depleted salt solution. Ammonia is removed continuously by in situ stripping; thus allowing gas production with a constant current efficiency (about 70%). Nitric acid up to 8 mol L-1 is obtained. The current efficiency of acid production depends on nitric acid concentration. When this concentration varies from 1 to 8 mol L-1 the average current efficiency is about 58%. Electrodialysis produces a rejected stream containing less than 3 x 10(-3) mol L-1 of ammonium nitrate.