Following the success of the first three IEEE Workshops on Computational Advances in Multi-Channel Sensor Array Processing, we are pleased to announce the fourth workshop in this series, sponsored by the Sensor Array and Multi-channel signal processing Technical Committee of the IEEE Signal Processing Society. CAMSAP 2011 will be held at the San Juan Marriott Resort in San Juan, Puerto Rico, and will feature a number of plenary talks from the world’s leading researchers in the area, special focus sessions, and contributed papers. To provide feedback to the authors and ensure a high-quality program, all papers will undergo peer review.