The trend of multicore processors development brings a shift of paradigm in applications development. Traditionally, increasing clock frequency is one of the main dimensions for conventional processors to achieve higher performance gains. Application developers used to improve performance of their applications by just waiting for faster processor platforms. Today, increasing clock frequency has reached a point of diminishing returns—and even negative returns if power is taken into account. Multicore processors, also known as Chip multiprocessors (CMPs), promise a power-efficiency way to increase performance and become more prevalent in vendors' solutions, for example, IBM CELL Broadband Engine processors, Intel Core 2 Dual processors, and so on. However, the application or algorithm development process must be significantly changed in order to fully explore the potential of multicore processors. This special issue of the Journal of VLSI Signal Processing Systems is to discuss related challenges, issues, case studies, and solutions, especially focusing on multimedia-related applications, architectures, and programming environments, for example, understanding the complexity of developing a new application or porting an existing application onto a multicore processor. (Call for papers)