It has become an important issue in recent years to extend the fatigue life of concrete structures, which are subjected to cyclic loading, by using FRP composites externally bonded to the structures (Kim & Heffernan 2008; Gheorghiu et al. 2006; Heffernan & Erki 2004). FRP-concrete interfacial debonding is one of the main failure modes of FRP reinforced concrete structures (Chen & Teng 2001). Therefore, it is of great importance to carry out studies on the interfacial crack propagation behaviour. However, the studies on the fatigue properties of FRP reinforced concrete structures have been limited. In particular, the studies on fatigue interfacial crack propagation behaviour of FRP reinforced concrete members were rarely reported (Diab et al. 2009; Ferrier et al. 2005; Nigro et al. 2011). In this paper, fatigue crack propagation behaviour of the CFRP-concrete interface was investigated experimentally and theoretically.