This volume of advances in soft computing and lecture notes in computer th science vols. 5551 5552 And 5553 constitute the proceedings of the 6 inter- tional symposium of neural networks isnn 2009 held in wuhan china during may 26-29 2009. Isnn is a prestigious annual symposium on neural networks with past events held in dalian 2004 chongqing 2005 chengdu 2006 n- jing 2007 and beijing 2008 . Over the past few years isnn has matured into a well-established series of international conference on neural networks and their applications to other fields. Following this tradition isnn 2009 provided an a- demic forum for the participants to disseminate their new research findings and discuss emerging areas of research. Also it created a stimulating environment for the participants to interact and exchange information on future research challenges and opportunities of neural networks and their applications. Isnn 2009 received 1 235 submissions from about 2 459 authors in 29 co- tries and regions australia brazil canada china democratic people s republic of korea finland germany hong kong hungary india islamic republic of iran japan jordan macao malaysia mexico norway qatar republic of korea singapore spain taiwan thailand tunisia united kingdom united states venezuela vietnam and yemen across six continents asia europe north america south america africa and oceania . Based on rigorous reviews by the program committee members and reviewers 95 high-quality papers were selected to be ...