IAEA safeguards symposia are important forums for interaction between the IAEA Secretariat and Member States concerning safeguards and verification issues. This publication is the proceedings of a symposium held in 2006 which addressed the challenges to the IAEA safeguards system that have emerged, or intensified, since the previous symposium in 2001. Reflecting developments since then, the symposium covered five topics: current challenges to the safeguards system, further strengthening of safeguards practices and approaches, improving the collection and analysis of safeguards information, advances in safeguards techniques and technology, and future challenges. These proceedings contain the addresses given at the opening session, the technical plenary session and the closing session. The summary provides an overview of the oral presentations at the 21 sessions of the symposium. The invited papers presented during the various topical sessions, as well as papers exhibited at the poster sessions, are available on the included CD-ROM.