Pervasive computing envisages a world of communicating miniature devices, sensors and actuators to provide ambient and personalised services. Building on the current technology, it is ready for a wide range of applications that support and gradually change our everyday life. The goal of ICPCA2009 is to further explore both theoretical and practical issues in pervasive computing. It also aims to foster the exchange of ideas and collaboration for both researchers and practitioners. The organising committee is soliciting paper submissions for the main conference and its special tracks. Following on the success of previous conferences in the series held in Urmqi, China (August 2006), Birmingham, UK (July 2007), and Egypt (October 2008), the 4th International Conference on Pervasive Computing and Appilcations (ICPCA2009) features one generic technical track as well as six special interest tracks.