Distributed Optical Fiber Sensors (DOFS) are gaining interest for structural health monitoring applications. Recently, they have been successfully used to monitor the strain profiles at the interface between concrete and steel or composite rebars during pullout tests. In the framework of durability studies on Glass Fiber-Reinforced Polymer reinforcing bars (rebars), this method offers interesting perspectives for monitoring the evolution of the concrete/rebar bond behavior under accelerated ageing conditions. However, the durability of the bonded DOFS instrumentation itself should be investigated in a preliminary stage, to assess possible alteration of its performance over aging, which would raise questions about the validity of strain measurements in the long term. This article presents the first results of an experimental program aiming to address this specific issue. In this work, steel rebars were equipped with bonded optical fibers. Half-length of the instrumented rebars was subjected to hydrothermal ageing by immersion in an alkaline solution, while the remaining length was exposed to standard laboratory conditions. After exposure, the rebars were tested in tension and the DOFS strain profiles were simultaneously measured. These strain profiles were then compared to reference measurements performed before ageing, providing insights on the influence of the ageing conditions on the response of the DOFS.