This dataset includes physical, biological and biogeochemical measurements of both the water column and seabed sediments. Hydrographic data include temperature, salinity, attenuance, dissolved oxygen, fluorescence, photosynthetically active radiation (PAR), sound velocity and current velocities, while biogeochemical analyses of water samples provided measurements of nutrients and biological sampling provided measurements of zooplankton abundance. A large number of benthic parameters were measured, including concentrations of substances such as nutrients, metals and carbon in both sediments and sediment pore waters. Benthic fauna were also studied, while rates of sedimentation flux were quantified. These oceanographic and benthic data were supplemented by satellite ocean colour imagery. The data were collected in the North Atlantic Ocean at the Mouth of Rockall Trough, Hatton-Rockall Basin and the Flank of Feni Drift between August 1997 and June 1999 over four cruises, comprising a preliminary site assessment (CD 107 August, 1997) followed by two process cruises (CD 111, April-May 1998, and CD 113, June-July 1998). A further cruise (CH 143) was part-funded by BENBO to retrieve moorings. The data were collected using a variety of instrumentation, including shipboard deployment of conductivity-temperature-depth (CTD) profilers with attached auxiliary sensors, benthic samplers, landers, cameras and incubation chambers, water samplers and continuous underway sensors. These were supplemented by moored sensor and satellite data. The BENBO programme was led by the Scottish Association for Marine Science/Dunstaffnage Marine Laboratory involved researchers from Southampton Oceanography Centre, Scottish Universities Research and Reactor Centre, Plymouth Marine Laboratory, Lancaster University, Leeds University, Edinburgh University, Cambridge University and the University of Wales, Bangor.