This book constitutes the proceedings of the second International Workshop on Advanced Computational Intelligence (IWACI 2009), following the successful IWACI 2008 held in Macao, China. IWACI 2009 provided a high-level international forum for scientists, engineers, and educators to present state-of-the-art research in computational intelligence and related fields. Over the past decades, the computational intelligence community has witnessed tremendous efforts and developments in all aspects of theoretical foundations, architectures and network organizations, modeling and simulation, empirical study, as well as a wide range of applications across different domains. IWACI 2009 offered a great platform for the community to share their latest research results, discuss critical future research directions, stimulate innovative research ideas, and facilitate international multidisciplinary collaborations. IWACI 2009 received 146 submissions from about 373 authors in 26 countries and regions across six continents. Based on rigorous peer reviews by the Program Committee members, 52 high-quality papers were selected for publication in this book, with an acceptance rate of 36.3%. These papers cover major topics of theoretical research, empirical study, and applications of computational intelligence.