The International Conference on Networking (ICN 2005) was the fourth conf- ence in its series aimed at stimulating technical exchange in the emerging and important field of networking. On behalf of the International Advisory Comittee, it is our great pleasure to welcome you to the proceedings of the 2005 event. Networking faces dramatic changes due to the customer-centric view, the venue of the next generation networks paradigm, the push from ubiquitous n- working, and the new service models. Despite legacy problems, which researchers and industry are still discovering and improving the state of the art, the ho- zon has revealed new challenges that some of the authors tackled through their submissions. In fact ICN 2005 was very well perceived by the international networkingc- munity. A total of 651 papers from more than 60 countries were submitted, from which 238 were accepted. Each paper was reviewed by several members of the Technical Program Committee. This year, the Advisory Committee revalidated various accepted papers after the reviews had been incorporated. We perceived a significant improvement in the number of submissions and the quality of the submissions. The ICN 2005 program covered a variety of research topics that are of current interest, starting with Gridnetworks, multicasting, TCP optimizations, QoS and security, emergency services, and network resiliency. The Program Committee selected also three tutorials and invited speakers that addressed the latest - search results from the international industries and academia, and reports on findings from mobile, satellite, and personal communications related to 3rd- and 4th-generation research projects and standardization.