IIH-MSP 2008 is the fourth International Conference on Intelligent Information Hiding and Multimedia Signal Processing. The conference this year is technically co-sponsored by IEEE, KES International, and Ubiquitous International and hosted by HARBIN INSTITUTE OF TECHNOLOGY with website http://iihmsp2008.hit.edu.cn. Multimedia technologies with an increasing level of intelligence are emerging to enable the process of creating a global information infrastructure that will interconnect heterogeneous computer networks and various forms of information technologies around the world. The conference is intended as an international forum for researchers and professionals in all areas of information hiding and multimedia signal processing. We invite submissions of papers presenting a high- quality original research and development for the conference tracks: (1) Information Hiding and Security, (2) Multimedia Signal Processing and Networking, and (3) Bio-inspired Multimedia Technologies and Systems.