Fretting-corrosion is a degradation mechanism taking place between two surfaces in contact, submitted to relative motion, load and electrochemical action. Material accumulated at the contact interface usually forms a friction film known as third body. This layer modifies and redistributes force and sliding velocity accommodation. Fretting corrosion is found in many applications such as biomedical implants, wires and nuclear power plants. Modelling of wear in fretting corrosion situations therefore needs to consider mass flow through the third bodies. In this paper we present a wear model based on the third body approach for describing degradation of titanium alloys under fretting corrosion. The model predictions were compared to literature experimental results. The overall good correlation found attest of the validity of the approach. Discrepancies between model and observations indicate that additional degradation mechanisms should be considered.