The phenomenal increases in computer system performance in recent years have been accompanied by a commensurate increase in power and energy dissipation. The latter has directly resulted in demand for expensive packaging and cooling technology, an increase in product cost, and a decrease in product reliability in all segments of the computing market. Moreover, the higher power/energy dissipation has signi cantly reduced battery life in portable systems. While – stem designers have traditionally relied on circuit-level techniques to reduce – wer/energy, there is a growing need to address power/energy dissipation at all levels of the computer system. We are pleased to welcome you to the proceedings of the Power-Aware C- puter Systems (PACS 2000) workshop. PACS 2000 was the rst workshop in its series and its aim was to bring together experts from academia and industry to address power-/energy-awareness at all levels of computer systems. In these p- ceedings, we bring you several excellent research contributions spanning a wide spectrum of areas in power-aware systems, from application all the way to c- pilers and microarchitecture, and to power/performance estimating models and tools. We have grouped the contributions into the following speci c categories: (1) power-aware microarchitectural/circuit techniques, (2) application/compiler power optimizations, (3) exploiting opportunity for power optimization in – struction scheduling and cache memories, and (4) power/performance models and tools.