Nanofluids are nanoscale colloidal suspensions containing condensed nanomaterials. Nanofluids have been found to possess enhanced thermos-physical properties such as thermal conductivity, thermal diffusivity, viscosity, and convective heat transfer coefficients compared to those of base fluids like oil or water. Boron Nitride (BN) nanoparticles - due to its high thermal conductivity, appropriate thermal expansion coefficient, high electrical insulation and high mechanical strength is a promising additive in traditional heat exchange fluids. In this work we synthesised Boron Nitride (BN) nanoparticles by hydrothermal method and the nanoparticles are characterized by XRD, EDAX and SEM. Nanofluids were prepared by different weight fractions of the nanoparticles in different ratio of water and Ethylene Glycol (EG) solution. Physiothermal properties of the fluids at different temperatures were investigated and the same is reported.