The International Workshop on Power and Timing Modeling, Optimization and Simulation (PATMOS) 2013 is the 23nd in a series of international workshops. The PATMOS meeting has evolved into a leading scientific event where industry and academia meet to discuss power and timing aspects in modern integrated circuit and system design. Both Universities and Companies are invited to participate. The PATMOS objective is to provide a forum to discuss and investigate emerging challenges in methodologies and tools for the design of upcoming generations of integrated circuits and systems, including reconfigurable hardware such as FPGA’s. The technical program will focus on timing, performance and power consumption as well as architectural aspects with particular emphasis on modeling, design, characterization, analysis and optimization.