The 5th International Conference on Natural Computation (ICNC'09) and the 6th International Conference on Fuzzy Systems and Knowledge Discovery (FSKD'09) will be jointly held in Tianjin, China. Tianjin is one of the four municipalities in China. It is a financial and commercial center in North China, which is known for its numerous travel resources and rich history, such as Gu Wenhua Jie, Dagu Emplacement, Huangyaguan Great Wall, Dule Temple, Haihe River, Panshan Mountain and Food Street. Tianjin Binhai New Area lies in the center of the Circum-Bohai Region and the eastern seaboard of Tianjin. It is located in the juncture of the Beijing-Tianjin City Belt and the Circum-Bohai City Belt. It is the gateway to North China, Northeast China, and Northwest China. Lying in the center of Northeast Asia, it is the nearest point of departure of the Eurasian Continental Bridge. ICNC'09-FSKD'09 aims to provide a high-level international forum for scientists and researchers to present the state of the art of intelligent methods inspired from nature, particularly biological and physical systems, with applications to data mining, manufacturing, design, and more. This is an exciting and emerging interdisciplinary area in which a wide range of theory and methodologies are being investigated and developed to tackle complex and challenging problems. Previously, the joint conferences in 2005 through 2008 each attracted over 3000 submissions from more than 30 countries. All accepted papers will appear in conference proceedings published by the IEEE Computer Society and will be indexed by both EI and ISTP. Extended versions of selected papers will appear in SCI-indexed journal(s).