Welcome Message The Internet is evolving at a frenetic pace, driven by exciting developments (in search, business, games, telephony, social networking, etc.) and in turn driving changes in traditional telecommunication networks. There is also an explosive proliferation of wireless devices (cellphones, sensors, etc.) that require network support. These have led to a rapid growth in the design and development of network-related hardware and software. Networks thus provide a rich source of problems for theoretical research. Conversely, they can benefit from the knowledge derived from theory. This conference seeks to facilitate such cross fertilization between theory and application. QTNA2009 aims to achieve impact through focus, in two ways: Each submission must promote queueing theory or related techniques, and demonstrate a relationship between theory and its application; any topic that satisfies these two requirements would be of interest. This conference is thus focused, yet broad. QTNA started as an Asia-Pacific Symposium, and the first three meetings were in Korea (2006), Japan (2007) and Taiwan (2008). The success of these symposia led to its elevation to an International Conference for 2009.