This book constitutes the refereed proceedings of the 12th International Conference on Parallel Computing, Euro-Par 2006, held in Dresden, Germany, in August/September 2006. The 110 revised papers presented were carefully reviewed and selected from 312 submissions. The papers are organized in topical sections on support tools and environments; performance prediction and evaluation; scheduling and load balancing; compilers for high performance; parallel and distributed databases, data mining and knowledge discovery; grid and cluster computing: models, middleware and architectures; parallel computer architecure and instruction-level parallelism; distributed systems and algorithms; parallel programming: models, methods, and languages; parallel numerical algorithms; distributed and high-performance multimedia; theory and algorithms for parallel computation; routing and communication in interconnection networks; mobile and ubiquitous computing; peer-to-peer and web computing; applications of high-performance and grid computing; high-performance bioinformatics; and embedded parallel systems.