In this study, we investigated the influence of nitrogen doping on thermal conductivity of carbon nanotubes (CNTs) experimentally and theoretically. The nitrogen-doped CNTs were synthesized by using thermal chemical vapor deposition method and were used to prepare silicone composites. The thermal conductivity of silicone composites with these CNTs improves greatly. A negative influence of nitrogen doping on thermal conductivity of CNT/silicone composites is observed. The calculated thermal conductivity of CNTs indicates that the thermal conductivity of nitrogen-doped CNTs decreases rapidly with the nitrogen content in CNTs. This is attributed to defects in nitrogen-doped CNTs, which act as phonon scattering centers. (C) 2015 Elsevier B.V. All rights reserved.