The author describes the bibliographic reconstruction of the library collection of Orenburg Theological Seminary suppressed in 1919 after the October Revolution. The problems of library collection reconstruction has been studied since the early 20-th century; however, with mainly the personal libraries of individual historical figures or families in the focus. Many methods of reconstruction have been developed. Their analysis examination demonstrates that the reconstruction in these cases is based on continuous looking through the collection in search of bookplates (ex libris), covers, book marks or other tags, or on searching and examining old inventories, library syllabi, and catalogs. However, when the major part of the collection is not preserved within other institutions, and the catalogs, syllabi and inventories do not exist anymore, these methods do not work. To reconstruct the library collection of Orenburg Theological Seminary with the lion’s share lost, the archival documents became almost exclusively the source of information on the library collection, namely teaching and educational reports, administration’s logbooks, bills, etc.