As one of the cost-effective machining methods for advanced ceramics, rotary ultrasonic machining (RUM) has attracted much attention and there exist numerous publications on the process. However, few investigations on tool wear in the RUM process have been reported. This paper, for the first time in literature, presents an experimental observation on tool wear in RUM of alumina. it presents and discusses the results on tool wear in RUM of alumina. It also discusses some practical implications of the findings from this study.