FRP materials are emerging as cost‐effective and high‐performing materials in various structural applications ranging from aerospace and defense to automotive, sporting goods, construction and transportation. These breakthroughs were achieved through better design practice and innovative manufacturing processes in addition to an understanding of the mechanisms governing the performance of these materials. Much of the developed expertise was confined to one composite material system, i.e., epoxy‐based composite materials. For emerging applications such as the rehabilitation of civil engineering structures and the oil industry, this material system is not cost‐effective when compared to conventional materials. Glass‐vinylester composites are considered a potential material system offering enhanced mechanical properties at a competitive cost. However, there is very little long‐term durability data related to their environmental performance and their resistance to corrosive fluids. In this paper, durability and environmental degradation of glass‐vinylester composites are evaluated when exposed to high temperature, moisture, seawater, and corrosive fluid. Polym. Compos. 25:609–616, 2004. © 2004 Society of Plastics Engineers.