We investigated the thermal conductivity of a fullerene peapod by molecular dynamics simulation. The thermal conductivity of a peapod was compared with that of a single-walled carbon nanotube (SWNT), and the reason for the difference between them is shown in this paper. Empirical potential functions of Brenner and Lennard-Jones potentials were used for those simulations. Thermal conductivity was calculated by Green-Kubo's equation. The results showed that the values of thermal conductivity of a peapod were larger than those of an SWNT due to the contribution of motion of fullerenes in the peapod. (C) 2007 Elsevier B.V. All rights reserved.