Six FRP-box beams loaded in bending, each having a length of 3 m, a height of 188 mm and a width of 118 mm, were tested under static and fatigue loading. In the short-time tests, these beams yielded similar failure loads to those of a HEA 200 steel beam. Two beams were tested under sinusoidal load-controlled conditions at a frequency of 2 Hz. The minimum load in each case was 4.8 % of the failure load, while the maximum load was 19.1 % in one case and 28.6 % in the other case. The beam fatigue tested at 19.1 % of the failure load did not develop any detectable damage before the test was terminated at 10⁸ cycles ( 1.59 years of loading). The bending stiffness of this beam after 10⁸ cycles was identical to that before testing. The beam tested at 28.6 % of the failure load showed no damage for the first 4.10⁶ cycles; at this point matrix cracks initiated on the matrix-rich surface of the bean on the tensile side. Even at 10⁸ cycles, the observed damage caused a decrease in bending stiffness of only 2 %.