In this paper, the results of the experimental investigation on the thermal properties of Nano fluid are presented. The effect of sonication time, settling time and temperature on the thermal conductivity, viscosity and specific heat of zinc oxide (ZnO, 14 nm and 25 nm size) and single walled carbon nanotube (SWCNT, 10nm size) based Nano fluid are investigated and the results of ZnO with DI water and ethylene glycol (EG) as base fluids are compared. The experimental results indicate that the studied parameters have a remarkable effect on the thermal properties of Nano fluid. The rate of enhancement in thermal conductivity of EG based Nano fluid is found to be less than that of water based Nano fluid. The SWCNT based DI water Nano fluid found to be very unstable i.e. the nanoparticles settle down very rapidly. The 0.02% volume fraction of SWCNT nanoparticles suspension results in 10% increase in the specific heat of DI water. A decrement of 24% and 13% in the specific heat of 14 nm size ZnO based Nano fluid were obtained at a volume fraction of 0.001% and 0.002% respectively.