Since the first International Hydrogenases Conference held in Szeged, Hungary in 1985, these successful meetings have been held every three years. As in the previous Hydrogenases Conferences, all fronts of fundamental and applied reseach on hydrogenases are covered in the scientific program, ranging from microbiology to chemical synthesis of biomedical compounds. Additionally, research on related redox (bio) catalysts for energy conversion, such as formate dehydrogenases, CO-dehydrogenases, and photosystems, is included within the scope of the conference