The international conference Personal Wireless Communications (PWC 2007) was the twelfth conference of its series aimed at stimulating technical exchange between researchers, practitioners and students interested in mobile computing and wireless networks. On behalf of the International Advisory Committee, it is our great pleasure to welcome you to the proceedings of the 2007 event. Wireless communication faces dramatic changes. The wireless networks are expanding rapidly in subscribers, capability, coverage, and applications, and costs continue to decrease. Mobile devices are becoming ubiquitous with greatly expanded computing power and memory, improved displays, and wireless lo cal and personal area connectivity. The PWC 2007 program covered a variety of research topics that are of current interest, starting with Ad~Hoc Networks, WiMAX, Heterogeneous Networks, Wireless Networking, QoS and Security, Sen sor Networks, Multicast and Signal processing. This year we enriched PWC with a poster session covering diversity topics related to wireless networks (e.g., fil ters, current conveyors, etc.). We would like to thank the International Advisory Committee members and the referees. Without their support, the program organization of this conference would not have been possible. We are also indebted to many individuals and organizations that made this conference possible (Czech Technical University, IFIP, ESTEC). In particular, we thank the members of the Organizing Commit tee for their help in all aspects of the organization of this conference.