Site 1231 of the Ocean Drilling Project (ODP) was characterized by low concentrations of organic carbon, as well as low cell numbers and biological activity rates. A 16S rRNA survey was performed in order to analyse the microbial community composition of these central oceanic sediments. Archaeal 16S rRNA genes from subsurface sediments at Site 1231 (1.8, 9.0, and 43 mbsf) were affiliated with uncultured lineages from subsurface or hydrothermal vent habitats. Members of the Marine Group I (MGI) found in the 1.8 mbsf sediment formed distinct clusters, some dominated by phylotypes from Site 1231 and other subsurface environments. The archaeal community survey at Site 1231 indicated that several archaeal lineages were widespread in subsurface environments, marine sediments as well as hydrothermal habitats.