First organized in 1994 to focus on nitrogenase and its unique iron sulfur chemistry, knowledge about iron sulfur clusters has grown exponentially in the last two decades, and in 2006, the name of the conference was accordingly changed to Iron Sulfur Enzymes. The conference has tremendous breadth, featuring sessions on numerous iron sulfur enzymes of unicellular organisms, animals, and plants, and important insights into how these versatile protein cofactors are synthesized and function. Proteins containing FeS cofactors perform a variety of biological functions ranging across electron transfer, acid-base catalysis, and sensing where they are agents for cell regulation through transcription (DNA) or translation (RNA). They are redox catalysts for radical-based reactions and the activation of H₂, N₂ and CO₂, processes that offer scientific and economic challenges for industry. Iron-sulfur centers provide the focus for fundamental investigations of chemical bonding, spectroscopy and paramagnetism, and their functions have numerous implications for health and medicine and applications for technology, including renewable energy. This conference will include distinguished speakers and discussion leaders from many fields, and topics will range from mechanistic discussions of bacterial enzymes to discussion of an emerging class of human diseases characterized by abnormalities in their iron-sulfur cluster biogenesis pathway.