In this research, the effect of adding carbon nanofibers (CNFs) on fatigue life of epoxy resin under flexural bending fatigue loading conditions was investigated. The fatigue tests of specimens were performed under displacement‐controlled bending loading at different displacement amplitudes at room temperature. Due to the addition of CNFs, a remarkable improvement in fatigue life of epoxy resin was observed. For instance, 24‐fold improvement in fatigue life for 0.25 wt% CNF/epoxy nanocomposites at a strength ratio of 0.43 observed in comparison with the neat epoxy resin.