The data set includes the classical oceanographic parameters of temperature, salinity, nutrients, oxygen, pH, alkalinity, and chlorophyll-a. This data set comprises more than 100,000 profiles collected by UK research and naval vessels in the shelf seas around the UK, the North Atlantic, the Norwegian Sea, the Barents Sea, the Mediterranean Sea, the South Atlantic, the Southern Oceans, the Indian Ocean, the Arabian Sea, the East Indian Archipelago (Indonesia) and the Pacific Ocean since the beginning of the twentieth century. In recent years, conductivity-temperature-depth (CTD) data have been collected in a higher resolution form than water bottle data; these have been included in this data set in a reduced resolution/water bottle form and merged with any available chemical parameters. This data set is one of the most complete of its kind in the world; the majority of the data known to have been collected prior to 1970 have been 'rescued' and work will continue to rescue the remainder. All of the profiles in this data set have been quality checked, cross-checked against original documentation, and all duplications removed. This data set has been compiled by the International Council for the Exploration of the Sea (ICES) Oceanographic Data Centre and is available from the ICES website.