The file contains an inventory of the archive of slides with fossil marine planktic diatoms from a network of sediment cores and surface sediment samples, including core tops. The collection of slides was prepared in NPI over the period from 1980s to 2019. The slides are packed in 83 diatom slide boxes and placed in 2 larger cardboard boxes (flytteeske) and 2 smaller cardboard boxes. The inventory file for each sediment core/surface sample provides the information on the sample ID, sample position (depth) in a sediment core, number of slides prepared from this sample, solution concentration and the slide location in the archive. Metadata also lists coordinates for some of the cores and the respective publications where the data were used.