In this paper, a two-dimensional numerical model is developed to simulate the performance of a heat pipe using various nanofluids. The effect of different nanofluids (prepared using alumina, copper oxide, and silver nanoparticles) at different concentrations and particle diameters on the performance of heat pipe is also studied by through finite volume method. The obtained results show that using a nanofluid instead of water leads to the increased thermal efficiency and reduction in heat at wall of the heat pipe. Also, the temperature difference between the evaporator and the condenser is a function of input power; this means that by an increase in the input capacity, the temperature difference between the evaporator and the condenser increases. It was observed that the use of nanofluid reduces the axial-flow pressure of the fluid inside the wick. As a result, the transmission of fluid flow inside the wick from the condenser to the evaporator is easily done with the cost of using a nanofluid. Moreover, with an increase in thermal capacity, fluid pressure drop becomes maximum and thus temperature difference between the evaporator and the condenser increases. (C) 2017 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.