The middleware technology used as the foundation of Internet-enabled enterprise systems is becoming increasingly complex. In addition, the various technologies offer a number of standard architectures that can be used by designers as templates to build applications. However, there is little concrete understanding in the software industry on the strengths and weaknesses of competing technologies, and the different trade-offs that various component architectures impose. The SACT Group at CSIRO has qualitatively and quantitatively evaluated a number of commercially available Message-Oriented Middleware (MOM) systems. This paper focuses on the results obtained from the performance evaluation of the IBM’s MQSeries V5.2. It presents an overview of the technology, and discusses the metric used in this study for performance measurement The test results related to the sustainable performance of the system using various test configurations are described and their implications discussed.