The major repository of technical reports at the Library of Congress is the Technical Reports Collections which are under the purview of the Library's Science Section and housed in a secure area of the Library's John Adams Building. Along with the millions of government-issued documents, the Technical Reports Collections also include a large number of technical reports distributed by foreign governments, universities and research institutes as well as a number of major international organizations. The majority of technical reports under the purview of the Science Section are not cataloged since they are typically fully described by various government or commercial abstracting and indexing services. The National Technical Information Service (NTIS), for example, maintains the National Technical Reports Library (NTRL) online database, while the Defense Technical Information Center (DTIC) operates the eponymous DTIC database.

However, there are also some materials in the Technical Reports Collections which do have brief catalog records -- at the bottom of the catalog records for these items, under "Item Availability" you will find the term, "UNCLASSED" and instructions to request the material in "ST&B Ref. desk Adams 5th fl, ask for Tech Repts 202-707-5655" or similar (See the linked record for an example).

These types of materials must be requested using the Ask-a-Librarian: Science and Technical Reports form or the "Research purpose or materials needed" field of the online form to schedule appointments, or in the case of materials from the Corporate Annual Reports and SEC Filings collections, from Business Section librarians directly or by using the Ask a Librarian: Business form for assistance, but they can also be requested in person at the Science and Business Reading Room reference desk, or by phone at (202) 707-5639.

Prior arrangements, made using the Ask-a-Librarian: Science and Technical Reports form, or appointment request form, are strongly encouraged, as requesting materials in advance gives librarians the opportunity to locate material and have it ready when the researcher arrives. Requests made at the desk will be fulfilled as staff are able, but those made outside core business hours may require significant additional time.

Uncatalogued technical reports and standards from the Technical Reports Collections or Standards Collection are serviced at the reference desk in the Science and Business Reading Room and must be used in the Reading Room. The Reading Room has microform readers as well as multi-function copier/printer/scanners, which can be used to copy, print or scan and email documents, and overhead scanners, which require thumb drives to store images. The reading room also possesses a computer center with public computer terminals, and one Stacks terminal, which can be used to view particular electronic content, only accessible onsite, such as those Office of Scientific Research and Development materials which have been digitized but not yet transferred to the Library's open digital collections.

About 1.5 million or so technical reports have been cataloged and are part of the Library's general collections. Records for these items include call numbers at the bottom of the catalog records for these items, under "Item Availability". Examples of these include the papers, notes, reports, and memoranda of the RAND Corporation, the reports of the North Atlantic Treaty Organization's  Advisory Group on Aerospace Research and Development (AGARD) and its successor organization, the Research and Technology Organization (RTO) and the various document series of the National Advisory Committee on Aeronautics (NACA), and its successor, the National Aeronautics and Space Administration (NASA). As a general rule, cataloged technical report series kept in the general collections are not duplicated in the uncatalogued Technical Reports Collections held directly by the Science Section.

General collection technical reports series may be found and requested through the Library's online catalog and used in whichever Reading Room they are delivered to. If a report cannot be found by author and/or title, the catalog can be searched for the series entry. These titles may be available in hardcopy, in microform, on digital media or in online databases.

Technical Reports published in Chinese, Japanese, or Korean must be requested in the Asian Reading Room. Reports published by the U.S. Government Printing Office and distributed as part of the federal document depository collection may be available for use in the Newspaper and Current Periodical Room in the Madison Building (LM 133).

The Microform Reading Room in the Jefferson Building has microform copies of some minor record groups. It also maintains a collection of U.S. doctoral dissertations on microform, published by UMI.

The following resources are print or microfilmed indexes, which can be used to identify technical reports. For uncatalogued technical reports held in the Science Section's Technical Reports Collections, a report number is required to locate material. These resources can provide that information.

Standards can be found in hard copy either in TRS collection, the Law Library (OSHA standards or some building codes for example), or searching the Library's online catalog for materials in the general collections. A selection of standards are also available in the Library's online databases. Print indexes include: