This volume contains the proceedings of the International Conference on Computer Aided Veri?cation (CAV), held in Edinburgh, Scotland, July 6-10, 2005. CAV 2005 was the seventeenth in a series of conferences dedicated to the advancement of the theory and practice of computer-assisted formal an- ysis methods for software and hardware systems. The conference covered the spectrum from theoretical results to concrete applications, with an emphasis on practical veri?cation tools and the algorithms and techniques that are needed for their implementation. We received 123 submissions for regular papers and 32 submissions for tool papers.Ofthesesubmissions, theProgramCommitteeselected32regularpapers and 16 tool papers, which formed the technical program of the conference. The conference had three invited talks, by Bob Bentley (Intel), Bud Mishra (NYU), and George C. Necula (UC Berkeley). The conference was preceded by a tutorial day, with two tutorials: - Automated Abstraction Re?nement, by Thomas Ball (Microsoft) and Ken McMillan (Cadence); and - Theory and Practice of Decision Procedures for Combinations of (First- Order) Theories, by Clark Barrett (NYU) and Cesare Tinelli (U Iowa). CAV 2005 had six a?liated workshops: - BMC 2005: 3rd Int. Workshop on Bounded Model Checking; - FATES 2005: 5th Workshop on Formal Approaches to Testing Software; - GDV 2005: 2nd Workshop on Games in Design and Veri?cation; - PDPAR 2005: 3rd Workshop on Pragmatics of Decision Procedures in - tomated Reasoning; - RV 2005: 5th Workshop on Runtime Veri?cation; and - SoftMC 2005: 3rd Workshop on Software Model Checking