Ignisphaera aggregans Niederberger et al. 2006 is the type and sole species of genus Ignis-phaera. This archaeal species is characterized by a coccoid-shape and is strictly anaerobic, moderately acidophilic, heterotrophic hyperthermophilic and fermentative. The type strain AQ1.S1 ^T was isolated from a near neutral, boiling spring in Kuirau Park, Rotorua, New Zeal-and. This is the first completed genome sequence of the genus Ignisphaera and the fifth ge-nome (fourth type strain) sequence in the family Desulfurococcaceae. The 1,875,953 bp long genome with its 2,009 protein-coding and 52 RNA genes is a part of the Genomic Encyclo-pedia of Bacteria and Archaea project.