The durability of FRP materials is a crucial factor in determining the suitability of these materials for widespread use. Unfortunately, there are currently not many structures using FRP reinforcement that have been in use for a significant period of time, which would allow us to assess the long-term performance of fiber-reinforced polymers. There are especially few structures with prestressed GFRP bars. As a result, design standards often include coefficients that reduce the strength of FRP materials in order to account for potential issues. Due to the lack of data, these coefficients are often applied conservatively. The purpose of this article is to deepen the understanding of the long—term characteristics of prestressed GFRP reinforcement under load in bridge structures. We will also demonstrate the remaining life of rods that have been in service conditions with combined effects of sustained loading and environmetnal exposure for more than 40 years. This paper investigates the durability GFRP rebars exposed to environment and subjected to pestressing. The test specimens were exctracted from the bridge with GFRP prestressed ties after more than 40 years in service. An extensive research was performed for extracted bars including tensile, compression and bending tests, Young’s modulus, alkali resistance tests, SEM. The results revealed some significant but not dramatic changes over the service period, including a 1.5% decrease in density, an 18% reduction in tensile strength, and a 26% drop in bending strength.