The Institute of Geological Sciences' very large collections of fossils originate from those made during geological surveying in Britain and are particularly valuable for tackling biostratigraphical problems. The fossils are distributed among various collections: the Type and Stratigraphical Collection is a selection of the best material and is used especially as a reference collection by the Institute's palaeontologists; the micropalaeontologica1 collections are increasingly important, notably for work on boreholes and the continental shelf; the Survey Collection is a large palaeontological and stratigraphical archive. The latter, together with the Boreholes Collection, are valuable for stratigraphical and a variety of other studies. Problems in curating microfossils and borehole material are discussed.