Mill wear is a critical issue in mineral industries. It affects mill performance and the cost of replacing worn parts is high. Understanding wear and its effect would provide a useful insight for process optimisation. This paper combines the discrete element method (DEM) with a commonly used wear model to predict the wear pattern of stirring discs in a model IsaMill. The results show that wear is more severe at the outer face of discs and the lifting side of holes. The simulated wear pattern has been compared with those observed in practice. The effect of disc wear on the flow of grinding media is also examined, showing that with the increasing wear, impact energy increases while power draw shows a mix of slight increase and decrease. The findings would be useful to the improvement in the design and control of IsaMills.