Particle shape and size of an energetic material play a vital role in achieving explosive formulations with optimal performance that decides the realization of high bulk and theoretical maximum density (TMD) and mix fluidity during their processing. 3-Nitro-1, 2, 4-triazol-5-one (NTO) is an insensitive thermally stable high explosive and explored as a potential replacement of RDX in explosive formulations. This study investigates the preparation of spherical NTO in NTO: water: 1-methyl-2-pyrolidone ternary system and the particle size management of spherical NTO by cooling crystallization technique. Crystallization operation variables like cooling rate, agitator configuration, speed, etc. have been systematically studied to understand their effect on the spheroidization process. Synthesized spherical NTO has been characterized by spectral, thermal and microscopic studies. The study established the process parameters to achieve selective particle size distribution ranging from 10 to 200 mu m. Bulk density of the spherical NTO has been determined and correlated with particle size distribution.