AbstractThe research undertaken during the last two decades has shown that one of the potential solutions to the steel‐corrosion‐related problems in concrete is the use of fiber‐reinforced composite (FRP) reinforcement as a replacement for traditional steel bars. Glass FRP (GFRP) reinforcement is gaining more popularity in construction of bridges and in other concrete structures because of its low cost compared to Carbon FRP reinforcement. The durability of these materials, especially under severe environmental conditions, is now recognized as the most critical topic of research. The lack of data on durability of the GFRP reinforcements is a major obstacle to their acceptance on a broader scale in civil engineering.This paper summarizes the most significant research work published on the durability of FRP bars in the past two decades. A comprehensive review of the literature on the durability of FRP bars indicates a significant increase in the number of studies in this area in the last decade. The durability tests conducted by the authors and others on the latest generation of GFRP bars subjected to stresses higher than the design limits, combined with aggressive mediums at elevated temperatures, have concluded that the strength reduction factors adopted by current codes and guidelines are conservative. These factors were based on limited test results that were carried out on the early generations of the GFRP products, which have now substantially changed.