In this paper, we present numerical and experimental studies on the nanoscale Joule heating along the single crystalline silicon nanowires. 50–100nm wide single crystalline silicon nanowires are heated via Joule heating by applying an electrical potential across them. Numerical simulation result predicts an extremely localized temperature field by resistive heating of silicon nanowire. We experimentally verified this highly localized heating of silicon nanowires by AFM imaging of localized thermal ablation of polytetrafluoroethylene (PTFE) thin film. This result implies potential applications of silicon nanowires as nanoscale heaters for the generation of highly localized temperature fields.