This book constitutes the thoroughly refereed post-proceedings of the 6th International Conference on Parallel Processing and Applied Mathematics, PPAM 2005, held in Pozna'n, Poland, in September 2005. The 135 papers presented were carefully selected and improved during two rounds of reviewing and revision. The papers are organized in topical sections on parallel and distributed architectures, paralel and distributed non-numerical algorithms, performance analysis, prediction and optimization, grid programming, tools and environments for clusters and grids, applications of parallel/distributed/grid computing, evolutionary computing with applications, parallel data mining, parallel numerics, and mathematical and computing methods. Contained as well are papers of the following workshops the 2nd grid application and middleware workshop (GAMW 2005), the 2nd grid resource management workshop (GRMW 2005), workshop on large scale computations on grids, workshop on scheduling for parallel computing, workshop on language-based parallel programming models, workshop on dependability of the distributed systems, workshop on HPC linear algebra libraries for computers with multi-level memories, and workshop on parallel bio-computing.