PMID vs PMCID: What’s the Difference?


PubMed is an index of the biomedical literature. A PMID, also known as the PubMed reference number, is a number assigned by the NIH National Library of Medicine to papers indexed in PubMed. PubMed Central is an archive of full-text journal articles. The National Library of Medicine assigns a PMCID, also known as a PMC Identifier, to each full-text paper in PubMed Central.

To comply with the public access policy, anyone submitting an application, proposal or report to the NIH must include a PMCID when citing applicable papers that they author or that arise from their NIH-funded research. If it helps to remember, think of the C in PMCID to indicate compliance with the public access policy.

While all abstracts appearing in PubMed are assigned a PMID automatically, NIH awardees may need to take action to obtain a PMCID.

Please remember you need to ensure papers are compliant with the public access policy as soon as the paper is accepted for publication. Try this interactive wizard to determine if your paper falls under the policy, how to bring it into compliance, and how to report it to NIH. We urge you to develop your public access plan as you are writing your paper!

Looking for more information? Visit the public access policy website or contact the help desk at


  1. What I really wish they did is set up PubMed so that the PMCID appears on the page of search results (in addition to the PMID)….

  2. I personally prefer PMID because PMIDs are easily found and can readily lead to full-length papers. In addition, all the reference managing software can show PMIDs, but not PMCIDs.

    1. As noted in section 4.4 of the SF 424 (RR) application guide, the instructions for the Bibliography and References Cited section indicate that citations that are required to comply with the public access policy (where authored or co-authored by the applicant and arose from NIH support), must use the PMCID. Publications not covered by the public access policy, but are publically available in a free online format, may include URLs or PMID numbers with the full reference.

  3. Providing the PMID number for manuscripts should be adequate to satisfy regulations on listing manuscripts in biosketches or linking publications to grants. The need for investigators to do extra work to ensure the assignment of a PMCID number adds a needless burden for no obvious gain.

  4. I am curious as to how well this policy even works (or, indeed, why it even exists) – I very much doubt that grant reviewers need to use the PMCIDs listed with the papers in our NIH Bios in order to locate them (at least, I hope they don’t!) and I cannot see many other people even being interested

  5. Entirely agree with Ian Frank – the PMCID requirements added an administrative burden with little apparent advantage.

  6. You are correct. The PMCID number has no additional value. It was added as one more regulatory steps to please the bureaucrats in Washington.

  7. I think the negative commenters here are missing the point. Public availability of full-text publications is a reasonable and appropriate expectation for research conducted with public funds. “Little apparent advantage?” Needless burden for no obvious gain?” Are you serious? Why *shouldn’t* you have to comply? Public access regulations are clearly stated conditions of award agreements when funds are accepted, and most journals will handle compliance for you, anyway. If it’s such a burden for you to make your results accessible to the public, I know dozens of PIs who would gladly take the money you’ve received instead, without complaining about the burden of accountability to those who fund the work.

    1. It’s dumb because the person who wants to view your work in the PMC database can simply look at the citation and find out if it’s there. Compliance is adding the paper to PMC. Citing the number is a pain in the a$$ and reviewers or the public can just as easily enter the pmid in pubmed and it is in in PMC there is a link. That’s more than adequate.

  8. I understand the need for the policy — so the tax-paying public can access the results of the research their tax dollars funded, without having to pay (again) to purchase the article from the publisher. However, compliance would be much simpler if you will:
    1. Allow authors to assign delegates to handle approvals, and copy delegates on all correspondence.
    2. Make manuscripts searchable by keyword (instead of “hidden”). This will be a major time-saver when determining next steps for compliance of a paper.

  9. I truly believe that any research sponsored by federal $$ should be made available to the public. I find the current strategy cumbersome as I receive so many error messages–perhaps that punishment for publishing. Perhaps an alternative solution would be to have someone [??? gov’t agencies] negotiate with journals to have all NIH/NSF/VA funded grants rendered open-access after 1 yr for a nominal fee.

  10. All grantees need to be aware of those journals that do not deposit automatically in PubMed. I could not find a list of biomedical journal with impact factor above say 2, that do not deposit. So far, the worst offended seems to be Science so beware…

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