This volume of the Lecture Notes in Computer Science series contains the set of papers accepted for the two co-located NGC/ICQT2003 workshops, i.e., the 5th COST 264 International Workshop on Networked Group Communications (NGC) and the 3rd - ternationalWorkshopon InternetChargingandQoSTechnology(ICQT),bothof which took place at the University of the Federal Armed Forces Munich (UniBwM), Germany and were hosted by the Information and Systems Laboratory, IIS. NGC2003wasthe ?fth workshopin a continuingseriesof highlysuccessfultech- cal meetings on group communications within the framework of the COST Action 264 "Networked Group Communications," following previous events in Pisa, Italy, 1999, Stamford, USA, 2000, London, UK, 2001, and Boston, USA, 2002. ICQT2003 was the latest edition of a vivid workshop on Internet economics and charging technology; previous events took place in the framework of the Annual Meeting of the German - ciety for Computer Science (GI) and the Austrian Computer Society in 2001 in Vienna, Austria, and in Zuri .. ch, Switzerland in 2002, co-located with the QofIS2002 workshop.