We determined the genome sequence of Arthrospira sp. PCC 8005, a cyanobacterial strain of great interest to the European Space Agency for its nutritive value and oxygenic properties in the Micro-Ecological Life Support System Alternative (MELiSSA) biological life support system for long-term manned missions into space. Whole-genome shotgun sequencing of strain PCC 8005 was performed using 454 pyrosequencing technology (amounting to 400,000 reads) and Sanger sequencing (up to 96,000 longer reads), leading to a final assembly of 119 contigs into 16 scaffolds representing 6,279,260 bases with an average GC content of 44.7%. These scaffolds were processed by the MaGe annotation platform (8) and predicted 5,856 protein-coding sequences (CDSs) and 176 genes encoding RNA. The PCC 8005 genome sequence and its curated annotation are important assets to better understand the physiology and metabolic potential of Arthrospira and will open up new opportunities in the functional genomics of this species.