This book constitutes the refereed proceedings of the 6th International Conference on Artificial Immune Systems, ICARIS 2007, held in Santos, Brazil, in August 2007.The 36 revised full papers presented were carefully reviewed and selected from 58 submissions. The papers are organized in topical sections on search and optimization, classification and clustering, anomaly detection and negative selection, robotics, control and electronics. Modeling papers, conceptual papers, as well as technical papers and general applications are also included.