A towed camera survey revealed extensive sponge aggregations on the deep slopes of the Rosemary Bank seamount in the NE Atlantic. An Agassiz beam-trawl deployed in the same area yielded samples for taxonomic validation and comparison to the visual survey. The sponge aggregations were observed between 1200-1400 m depth and were dominated by the two classes, Demospongia and Hexactinellida. Ten species wwere identified in the trawl samples from six genera; Geodia, Thenea, Pheronema, Aphrocallisters, Aplysilla and Craniella. Of these seven taxa were consistently identified in video footage. Thenea sp. was numerically dominant across all depths, but other species showed significant change in abundance with depth. At shallower depths Pheronema carpenteri was more prevalanet, whereas Aplysilla sulfurea increased in frequency with depth. Although all species have been previously resported from the North Atlantic, community composition and diversity at Rosemary Bank appear to be different from other regions. Estimates of the number of sponges within the surveyed area suggest around 80 million sponges may be present. The community appears to be largely in pristine condition and the recent designation of Rosemay Bank as a nature conservation MPA should help to ensure it remains so.