This book constitutes the refereed proceedings of the 22nd International Conference on Architecture of Computing Systems, ARCS 2009, held in Delft, The Netherlands, in March 2009. The 21 revised full papers presented together with 3 keynote papers were carefully reviewed and selected from 57 submissions. This year's special focus is set on energy awareness. The papers are organized in topical sections on compilation technologies, reconfigurable hardware and applications, massive parallel architectures, organic computing, memory architectures, enery awareness, Java processing, and chip-level multiprocessing.