The library of the Real Jardín Botánico forms part of the CSIC Library Network. It is a specialised library, supporting teaching and scientific research in botany. Its holdings comprise approximately 32,000 books, 2,075 periodicals, 27,000 brochures or off-prints, 3,000 titles on microfiche, 2600 maps and 60 CD-ROMs. The catalogue can be queried online via the bibliographical catalogue of the CSIC's Library Network (Access to the catalogue) .
- Books from the 16th, 17th and 18th centuries, including three incunnabulae.
- Floristic works and floras, primarily of Spain, Western Europe, the Mediterranean Region and Latin America, and the most important recently published works.
- Monographic works dedicated to the taxonomic study of the different groups of plants, primarily fungi, bryophytes and vascular plants.
- Basic works for the study of botany, such as general treatises, bibliographic repertoires, catalogues of periodical publications, indices of scientific names and popular names, chromosome numbers, abbreviation standards, geographical standards, etc. and basic treatises for the study of systematics and evolution.
- Historical works, particularly those dealing with Spain, Latin America and the scientific expeditions promoted by the Spanish crown.
- Gardening books, including those dedicated to practical issues, as well as historical gardening books and books on garden design.
- Books on medicinal plants, useful plants or popularly used plants, primarily those found in Spain or of greatest economic importance.
- The books are sorted according to the CDU, which has been expanded and modified to adapt it better to holdings relating to gardening subjects, botanical books published before 1753, and classic or basic botanical works, floristic works and floras, and botanical monographs.
- The periodical publications and brochures are shelved by accession number.
- Book microfiches are arranged alphabetically by author and journal microfiches alphabetically by title.
- The maps are arranged by types and countries.