VARI 2011 was the second European workshop on CMOS Variability. The VARI meeting answers to the need to have a European event on variability, where industry and academia meet to discuss. VARI 2011 was organized by CEA-Leti. The objective of VARI was to provide a forum to discuss and investigate the CMOS variability problems in methodologies and tools for the design of upcoming generations of integrated circuits and systems. The technical program focused on timing, performance and power consumption as well as architectural aspects with particular emphasis on modeling, design, characterization, analysis and optimization of variability. A selection of papers on CMOS variability presented at VARI 2011 is included in this special section of JOLPE. The selection of the papers has been done based on the peer reviews of the VARI workshop, the quality of the presentations and the feedback and comments received during and following the workshop. The papers included in this special section are extended and updated versions of the original VARI papers. This special section combines a workshop focusing on CMOS variability for power and power optimization with a journal targeting the same technologies. This will definitely boost the dissemination of the latest research results in the scientific community on power optimizations considering variability.