Skip Navigation Bar

FAQ: MEDLINE Indexing Requirements for Electronic Journals

  1. What is the NLM policy for electronic journals that are indexed in MEDLINE?
    The NLM MEDLINE Policy on Indexing Electronic Journals can be found at This policy applies to electronic journals that are indexed in the MEDLINE database.

    As journal publishing evolves, the journal of record for many publications is the online version, with much material only appearing online and not in a print equivalent of the journal. The NLM policy for indexing articles from electronic journals is also evolving and the following requirements will initially apply to electronic-only journals. However, this policy will be expanded in the future to include publications where substantial content is available only in the online version of the publication.

    Initially, the updated policy will apply to electronic-only journals which have applied for and been recently approved for inclusion in MEDLINE and journals currently indexed in MEDLINE that have switched or will switch to being electronic-only. There are three required conditions that electronic journals must meet in order for the journal to be indexed in MEDLINE:
    1. Provide NLM with XML-tagged data of its bibliographic citations.
    2. Provide robust current access to all its content under a license allowing efficient support of NLM operations, onsite services, and interlibrary loan.
    3. Have an acceptable arrangement for permanent preservation of, and access to, the published content.

    For conditions 2 and 3, NLM must be satisfied that all articles published in an electronic journal are available in a digital archive. We seek to ensure that our users will always have access to the full text of every article cited in MEDLINE. The permanent archive must be either by:
  2. When does the MEDLINE Policy on Indexing Electronic Journals go into effect?
    NLM will begin the implementation of this policy beginning May 1, 2011, focusing on electronic-only journals at this point. NLM will work with electronic-only journals approved for MEDLINE indexing in 2010, but where indexing has not yet begun, to offer these journals the options available in the new policy.

    There are also instances where journals currently indexed in MEDLINE have switched or may switch over to being electronic-only publications. NLM will notify these journals about the new electronic journal indexing policy, and will provide a generous timeframe to allow these journals to comply with the policy so their inclusion in MEDLINE will continue.

  3. What is meant by a "certified" archive?
    NLM is interested in ensuring that journal material is being placed in an archive that meets standards acceptable to NLM for archiving and preservation. Though participation in PubMed Central is the NLM preferred mechanism, NLM agrees with the certification process for third-party archives according to the Trustworthy Repositories Audit and Certification Checklist (TRAC) and other metrics developed by the Center for Research Libraries.

  4. Where do I get information on participating in PubMed Central?
    General information about PubMed Central is available at Details on participating in PubMed Central are found at (How to join PMC).

  5. When should the PDF/A files be submitted?
    For electronic journals submitting their content to a third-party archive, PDF/A files should be submitted to NLM for all of their journal content that is indexed in MEDLINE. The PDF/A files should be submitted at the same time as the XML bibliographic citation data are submitted. Each citation that is submitted via XML should have an accompanying PDF/A file. Details on how to submit XML data and the PDF/A files are found at (XML Help for PubMed Data Providers).

    NLM will work with a journal to ensure that it can be compliant with the indexing policy. It may take several months for a journal to be able to provide the expected PDF/A files along with the XML bibliographic citation data; NLM is willing to work with publishers in this situation.

  6. What will happen to an electronic journal that is not able to provide PDF/A files?
    In order for an electronic journal to continue to be indexed in MEDLINE, and thus be accessible in PubMed, the journal must comply with all aspects of the MEDLINE Policy on Indexing Electronic Journals. If a journal is not able or willing to adhere to the policy, future issues of the journal will not be indexed. Previous citations found in the MEDLINE/PubMed database will be retained but no future citations will be included in MEDLINE.

  7. How does the MEDLINE Policy on Indexing Electronic Journals relate to compliance with the NIH Public Access Policy?
    The MEDLINE Policy on Indexing Electronic Journals is not related to the NIH Public Access Policy; compliance with one policy does not result in compliance with the other policy. Fulfillment of the electronic journal indexing policy does not take the place of or supersede the compliance requirements stated by the NIH Public Access Policy. NIH grantees are required to comply with the NIH Public Access policy as stated at

    Journals approved for indexing in MEDLINE have been reviewed because the journal editor or publisher has applied for inclusion in MEDLINE. The Policy on MEDLINE Indexing Electronic Journals pertains to electronic journals that have been selected for indexing in MEDLINE. It is the journal's responsibility to adhere to this policy in order to ensure that its articles are indexed in MEDLINE.

  8. Can articles supported by NIH grant funds meet the NIH Public Access Policy by submitting content to a third-party repository?
    No. In order for an NIH grantee to be compliant with the NIH Public Access Policy, the grantee must adhere to the compliance requirements as stated at the site. If a journal is making a manuscript or article submission for an NIH grantee, the journal must adhere to the directions given at the NIH Public Access Policy Web site at Submission to a third-party repository does not meet the Public Access compliance specifications.
  9. What are NLM's expectations about the interlibrary loan (ILL) requirement?
    NLM defines "efficient" interlibrary loan as the ability to fulfill interlibrary loan requests: 1) Using a delivery method that is acceptable to the requesting library. Publishers are required to allow ILL via post, fax, and 2 out of the following 3 electronic delivery methods: proprietary vendor electronic delivery system*, web delivery, or email; and 2) Without regard for the geographic location of the requesting library. If an electronic journal is subject to the MEDLINE Policy on Indexing Electronic Journals, and requires a license for access, then the license must allow the National Library of Medicine to provide interlibrary loan as described above.

    If more than one title is licensed from the same publisher, and at least one title is subject to the MEDLINE Policy on Indexing Electronic Journals, then all titles subscribed to from that publisher by the National Library of Medicine, and covered by the license agreement, must be provided with the same interlibrary loan terms. Any new titles added to the license will also be under the same terms. If an existing license does not contain satisfactory language related to interlibrary loan terms then the license must be amended before indexing can commence or continue.

    NOTE: NLM fills interlibrary loan requests in accordance with Section 108 of the United States Copyright Law (17 USC Sec. 108, "Limitations on exclusive rights: Reproduction by libraries and archives") and clause 3 of the Guidelines for the Proviso of Subsection 108(g)(2) prepared by the National Commission on New Technological Uses of Copyrighted Works.

    *Ariel, Odyssey are examples of proprietary vendor electronic delivery systems.