The 2009 Gordon Conference on Antimicrobial Peptides will present the latest research on the biology and activities of antimicrobial peptides, essential and multifunctional host defense molecules employed by all organisms for innate defense. The Conference will feature a wide range of topics, such as structure/function analysis, regulation of expression, mechanisms of action, microbial avoidance strategies, human disease associations and model systems, and development of antimicrobial peptides as therapeutics. Invited speakers represent a diverse variety of scientific disciplines, including biochemistry, molecular genetics, microbiology, animal and plant biology, structural biology, medicine, innate immunity, signaling, and drug development. The Conference will bring together a collection of investigators who are at the forefront of their field, and will provide opportunities for junior scientists and graduate students to present their work in poster format and exchange ideas with leaders in the field. Some abstracts and poster presenters will be selected for short talks. The collegial atmosphere of this Conference, with programmed discussion sessions as well as opportunities for informal gatherings in the afternoons and evenings, provides an avenue for scientists from different disciplines to brainstorm and promotes cross-disciplinary collaborations in the various research areas represented.