From a design point of view, the mechanical behavior of the material is crucial to choosing the appropriate material and geometry for the assumed boundary conditions. This chapter presents experiments investigating the mechanical performance of fiber-reinforced bars for concrete reinforcement, but is not limited to this aspect alone. Although composite materials have been well-known for decades, they are still not commonly used in civil structures. It is caused by limited standards for mechanical testing as well as different design strategies in comparison to commonly used engineering materials. This chapter includes the results of the authors’ experimental campaign to investigate the mechanical properties of bars manufactured at Wroclaw University of Science and Technology by the modified pultrusion process.