This book constitutes the refereed proceedings of the 20th International Conference on Cutting-Edge Research Topics on Multiple Criteria Decision Making, MCDM 2009, held in Chengdu/Jiuzhaigou, China, in June 2009. The 72 revised full papers presented together with 49 short papers were carefully reviewed and selected from 350 submissions. The papers are organized in workshops on evolutionary methods for multi-objective optimization and decision making; text mining, semi-structured, web, or multimedia data; knowledge management and business intelligence; data mining based extension theory; intelligent knowledge management; meta-synthesis and complex systems; risk correlation analysis and risk measurement; optimization-based data mining method and applications; risk analysis with multiple criteria decision making; applications of decision theory and method to financial decision making; hybrid MCDM techniques for problems-solving.