In this paper investigated the effect of cetyltrimethylammoniumbromide (CTAB) surfactant of heat pipe thermal performance usingTiO2-water nanofluid as the working fluid. TiO2 nanofluids was prepared using titanium dioxide nanoparticles (TiO2 NPs) and modified with CTAB as cationic surfactant. The particles size of TiO2 NPs used in these experiment were 21 nm and density of 130 g/L. The base working fluid was demineralized water. The TiO2-water nanofluid was prepared using a one step method by mixing method under ultrasonication for 10 minutes, TiO2 NPs concentration of 8% volumetric loading, demineralized water of 100 mL, pH was adjusted at 8, and CTAB of 0.029 w.%. Thermal resistances of the heat pipe containing the TiO2-CTAB surfactant (2.8 W°C-1) was lower than those found in TiO2 NPs (3.12 W°C-1) and pure deminerilized water as the working fluid (5.71 W°C-1). The TiO2 nanoparticles and cationic surfactant has an important role to reduce the thermal resistance in the heat pipe (2.9 W°C-1). The TiO2 system and TiO2-surfactant nanofluid can be decreased the temperature in the wall of heat pipe until 32 and 36%, respectively. The TiO2 NPs and CTAB cationic surfactant has an important role to reduce the thermal resistance in the heat pipe. This field of research has a great potential for improvement the thermal conductivity of TiO2 nanofluid that can be applied as heat transfer in the heat pipe. The addition of cationic surfactant into the nanofluid can be used to minimize nanoparticles aggregation and improve the dispersion behavior of nanofluid.