Nano-hexagonal boron nitride (h-BN) was successfully prepared via rapid microwave-assisted synthesis using boric acid (H3BO3) and melamine (C3H6N6) as raw materials. An investigation of the effect of the microwave energy on the synthesis process of nano h-BN was carried out. In addition, the preparation method of the precursor was also studied. Here, mixtures at different H3BO3:C3H6N6 ratios (1:1 and 2:1 M) were prepared via wet and dryforms. Each precursor was heated under microwave energy for different reaction times. The microwave-synthesized nano-products were characterized by XRD, SEM, EDS, HRTEM and SAED. The results show that the reaction time and temperature that are typically 4.6 h (ramp time + soak time) and 1400-2100 degrees C, respectively (literature values), can be dramatically reduced to only 1.5 h (ramp time + soak time) and 1130-1210 degrees C, respectively, applying microwave heating. It was observed that the final product consists of crystalline h-BN nanoparticles of about 20 nm and disc-like morphology. (C) 2020 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.