Isosphaera pallida (ex Woronichin 1927) Giovannoni et al. 1995 is the type species of the genus Isosphaera. The species is of interest because it was the first heterotrophic bacterium known to be phototactic, and it occupies an isolated phylogenetic position within the Planc-tomycetaceae. Here we describe the features of this organism, together with the complete genome sequence and annotation. This is the first complete genome sequence of a member of the genus Isosphaera and the third of a member of the family Planctomycetaceae. The 5,472,964 bp long chromosome and the 56,340 bp long plasmid with a total of 3,763 pro-tein-coding and 60 RNA genes are part of the Genomic Encyclopedia of Bacteria and Arc-haea project.