Description:This book constitutes the thoroughly refereed postconference proceedings of the 6th International Andrei Ershov Memorial Conference, PSI 2006, held in Akademgorodok, Novosibirsk, Russia in June 2006. The 30 revised full papers and 10 revised short papers presented together with 5 invited papers were carefully reviewed and selected from 108 submissions during two rounds of evaluation and improvement. The papers address all current aspects of theoretical computer science, programming methodology, and new information technologies, which are among the most important contributions of system informatics.