Approximately 1 million books in the closed stacks, 70.000 directly accessible in the reading rooms.
Approximately 3.800 titles, whose 1.300 current, all directly accessible to the users (current issues and back volumes issues, more than 70.000 volumes).
Foreign periodicals concerning the Library different specialized subject areas are almost 800.
Accessible from Pontifical Gregorian University:
- concerning Theology, Sacred Scripture, Patrology, Philosophy, Psychology, Social Sciences, National bibliographies, Encyclopaedias and Directories;
- more than 1.900 concerning Library different specialized subject areas. Many of these electronic periodicals are subscribed by the Library also in the printed version;
- , portal to thousands of electronic journals.
Riserva Collection, approximately 30.000 antique books: incunabula, sixteenth century, precious books, rare editions. Content coverage is mainly related to theology, history, patrology, literature, spirituality, law, liturgy and sciences);
Wetter Collection, born as Bibliotheca Scriptorum Russorum and later named Centre for Marxist Studies, is a large collection of monographs and periodicals (42.000 volumes) concerning russian and sovietic philosophy and literature, contemporary atheism, marxism;
Hagiographic Collection, collection of documents concerning beatifications and canonizations (more than 2.000 volumes);
SIDIC Collection, collection of 6.300 books concerning the interreligious dialogue between Christians and Juifs. This collection has been given to the Library by SIDIC - International Juifs-Christians Documentation Service in 2001;
Vedovato Collection, approximately 4.600 books, many written in various languages (Italian, French, English, Russian, Chinese, Ethiopic) and published in the 20th and 21st centuries. The collection content coverage is related to social sciences and humanities, in particular universal modern and contemporary history, economics, international law, European Union law, Italian law, human rights and the fundamental freedoms, European Institutions and Organizations, geography and historical, artistic and religious Italian heritage;
Biblioteca Europea Vedovato Collection, approximately 35.000 publications concerning the 20th Century History (mainly Europe and Africa), European integration processes, international relations, Italian parliamentary and diplomatic history;
Maurizio Fagiolo dell'Arco Collection, more than 3.000 publications concerning the Art History, particularly the Baroque Art History;
Doctoral Dissertations Collection, more than 20.000 doctoral dissertations, more than 6.300 of them are Gregorian University dissertations