This research experimentally investigates the effects of an impact event during fatigue loading of a CFRP structure. Open-hole specimens were impacted in-situ during a short interruption of a tension-tension cyclic loading program. The impact was aimed directly below the central hole, with the critical fatigue damage path being left and right of this hole. A combination of digital image correlation (DIC), acoustic emission (AE) and C-scan measurements was used to measure the material response and damage patterns. The results indicate that while an impact caused the total amount of damage to increase as one would expect, its effect on the damage along the critical path depends on the timing of the impact. Only an impact before fatigue clearly accelerated fatigue damage accumulation leading to a shorter fatigue life. In contrast, impacting specimens at a later moment during fatigue loading had no effect on this critical damage accumulation.