In the present study, an experimental investigation is performed to determine the performance of the grooved heat pipe using DI water and Iron Oxide nanofluid as the working fluid. The average diameter of DI water and Fe2O3 nanoparticles is 50 nm. In this analysis the parameters considered are heat input, angle of inclination and filling ratio of the working fluid in the evaporator section. The experiment has been conducted with varying heat inputs from 30 to 70 W with 10 W intervals, inclination angle varies from 0° to 90 ° with 15° interval, filling ratio is 75 % with constant flow rate of coolant in the condenser section as 0.08 kg/min. The efficiency and thermal resistance of the grooved heat pipe has been determined and it was observed that Fe2O3 nano fluids produces better results when compared to the DI Water and 45°orientation of the heat pipe has more excellent performance.