Description:This book constitutes the refereed proceedings of the 12th International Symposium on Static Analysis, SAS 2005, held in London, UK in August 2005, co-located with the International Symposium on Logic-based Program Synthesis and Transformation (LOPSTR 2005).The 22 revised full papers presented together with the abstracts of 2 invited talks were carefully reviewed and selected from 66 submissions. The papers address all aspects of static analysis including program and systems verification, shape analysis and logic, termination analysis, security and safety, abstract interpretation and algorithms, abstract domain and data structures, pointer analysis, shape analysis, and data flow analysis.