[EN] In recent years the use of fiber reinforced concrete (FRC) in the construction industry has increased significantly, supported by research advances and new codes. These materials have important advantages compared to traditional reinforcing concrete. Synthetic fiber reinforced concrete (SNFRC) leads to improvements in terms of concrete service behavior, increased durability due to reduction of crack width and permeability. However, there is concern about the influence that the sensitivity of SNFRC to temperature changes may generate due to its effect on the properties of plastics. For this reason, it was decided to study the effects that cause differences in temperatures in a range defined as moderate (-15 ° C, 20 ° C and 60 ° C) on concrete reinforced with polymeric fibers. The concept of "moderate" refers to the fact that this range is limited to values ¿¿that cover most of the thermal levels that can occur in some part of the inhabited world with relative frequency. An experimental program was carried out focused on the evaluation of the three-point bending behavior on specimens conserved at the selected temperatures and adapting the test of the UNE-EN 14651 standard to be able to apply the load while keeping said temperature constant. Compressive strength, fresh concrete properties such as consistency and air content were also analyzed. TFGM