Many cumulative damage theories have been used in lifetime calculation of GFRP composite components. However, it is well known that linear damage accumulation models are inadequate for predicting the cumulative damage in GFRP compositeas due to their dominant viscoelastic characteristics. This paper discusses the outcomes of application of damage accumulation models proposed by Palmgren-Miner [Miner MA. Cumulative damage in Fatigue. J Appl Mech 1945;12(September):A159–64], Broutman and Sahu [Broutman LJ, Sahu SA. New theory to predict cumulative fatigue damage. In: Fiberglass reinforced plastics, composite materials: testing and design (second conference), ASTM STP 497; 1972. p. 170–88], Hashin and Rotem [Hashin Z, Rotem A. A cumulative damage theory of fatigue failure. J Mater Sci Eng 1978;(34):147–60] and Epaarachchi and Clausen [Epaarachchi Jayantha A, Clausen Philip D. On predicting the cumulative fatigue damage in glass fibre reinforced plastic (GFRP) composites under step/discrete loading. Composites Part A: Appl Sci Manuf 2005;36(9):1236–45], to calculate the lifetime of GFRP composite samples under repeated block loading situations.