A recently completed pre-standard for load and resistance factor design of pultruded fiber-reinforced polymer structures includes an S-N fatigue life prediction model for the design of components, which will experience cyclic loading. The prediction is independent of material and geometric properties and is shown to be overly conservative when applied to experimental data. A different model, developed at the Constructed Facilities Center at West Virginia University, is combined with the pre-standard model in order to incorporate material and geometric properties and improve life prediction accuracy from an over-prediction of 50× cycles to failure to only 5×.