The dataset contains hydrographic, biogeochemical and biological measurements of ocean and seabed sediment properties. Hydrographic profiles provided measurements of temperature, salinity, dissolved oxygen and fluorescence to accompany biogeochemical and biological samples, including concentrations of nutrients, particulate organic carbon (POC) and particulate organic nitrogen (PON). Emphasis was placed on the collection of benthic data, with numerous core samples being collected and analysed for pigments, biomarkers, lipids and other organic compounds. Samples were also collected and analysed for Holothurian species, while a large volume in situ filtration system was used to measure biogeochemical variables including POC and PON, and particulate iron. Station data were supplemented by continuous underway measurements of bathymetry, current velocities, sea surface salinity, temperature, fluorescence and beam attenuation across the survey area. These were accompanied by underway measurements of surface meteorological parameters including irradiance, air temperature, humidity, sea level pressure and wind velocities. The data were collected across the Crozet Plateau in the Southern Indian Ocean between 1st December 2005 and 14th January 2006 on RRS Discovery cruise D300. Data collection focused on four sites, with repeated hydrographic profiles, water and sediment samples collected at each location. In total, 89 instrumentation deployments were carried out at the four stations, including a conductivity-temperature-depth (CTD) package and a Megacorer (for sediment sampling). The underway system utilised a hull-mounted acoustic Doppler current profiler (ADCP) as well as a thermosalinograph and other standard surface hydrographic and meteorological instruments. Further data were collected using a variety of equipment including an otter trawl (net) and submersible cameras but these data are currently held by the data originators and are undergoing processing so are not included in the parameter and instrument lists above. The principal objective of Benthic CROZEX was to assess the manner in which biogeochemical composition and flux of organic matter to the deep-sea floor drives benthic community structure, dynamics and diversity at sites with contrasting primary production regimes. Investigators from British Antarctic Survey (BAS), Natural History Museum (NHM), National Oceanographic Centre (NOC) and the National University of Ireland, Galway (NUIG) were involved. Data management is being undertaken by the British Oceanographic Data Centre (BODC) but data processing is ongoing and various data are yet to be submitted to BODC.