Welcome to the proceedings of PATMOS 2003. This was the 13th in a series of international workshops held in several locations in Europe. Over the years, PATMOS has gained recognition as one of the major European events devoted to power and timing aspects of integrated circuit and system design. Despite its significant growth and development, PATMOS can still be considered as a very informal forum, featuring high-level scientific presentations together with open discussions and panel sessions in a free and relaxed environment. This year, PATMOS took place in Turin, Italy, organized by the Politecnico di Torino, with technical co-sponsorship from the IEEE Circuits and Systems Society and the generous support of the European Commission, as well as that of several industrial sponsors, including BullDAST, Cadence, Mentor Graphics, STMicroelectronics, and Synopsys. The objective of the PATMOS workshop is to provide a forum to discuss and investigate the emerging problems in methodologies and tools for the design of new generations of integrated circuits and systems. A major emphasis of the technical program is on speed and low-power aspects, with particular regard to modeling, characterization, design, and architectures.