Guanylurea dinitramide (GUDN), a stable salt of dinitramidic acid has good thermal stability and is a potential candidate for insensitive munitions. The synthesis process involves nitration of the ammonium salt of sulfamic acid with conc. HNO3/H2SO4 at -20 degrees C to -50 degrees C and further treatment with an aqueous suspension of guanylurea sulfate to obtain GUDN as white crystalline solid in 50% yield. In order to optimize the process parameters to get the product in higher yield and greater purity, a systematic study with variation of different parameters like molar ratio of nitrating mixture, conditioning time, and temperature was carried out.