Artificial Intelligence research has made substantial progress since the 1950s. However, many state-of-the-art intelligent systems are still not able to outperform human intelligence. To advance the research in artificial intelligence, it is beneficial to investigate intelligence, both artificial and natural, in an interdisciplinary context. The objective of this workshop is to bring together researchers from brain science, cognitive science, and artificial intelligence to explore the essence and technology of intelligence. This workshop provides a platform to discuss some key issues in intelligence science: (1) What new methodologies and ideas may cognitive science and brain science bring into the research of artificial intelligence? (2) What are the underlying algorithmic principles and circuitry wiring of the observed intelligent behaviors? (3) How are intelligent behaviors realized as hierarchical organization of functions across multiple modalities and time scales? (4) What are the key problems of intelligence science that requires joint research in brain science, cognitive science, and artificial intelligence? This workshop takes advantage of IJCAI-13 by hoping to attract participants from academia and industry worldwide. The communication among researchers from these fields will strongly boost the understanding of intelligence, provoke new theories on intelligent behaviors and lead to new experiments or systems. The workshop is to be held at the beginning of IJCAI-13, August 3-4, 2013. Workshop participants will have the opportunity to meet and discuss issues with a selected focus — providing an informal setting for active exchange among researchers and developers on topics of common interest.