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Number of Titles Currently Indexed for Index Medicus® and MEDLINE® on PubMed®

As of August 1, 2018, 5,234 journals are currently indexed for MEDLINE. MEDLINE includes journals that are cited as Index Medicus as well as other non-Index Medicus journals. A breakdown is provided:

Number of Journals Subset of Journals Currently Indexed*
4,953  journals indexed as Index Medicus
281  additional, non-Index Medicus journals in the following areas:
  53 Dentistry (contribute to Citation Subset=D)
  1 AIDS/HIV (contribute to Citation Subset=X)
  7 Consumer Health (contribute to Citation Subset=K)
     109 Nursing (contribute to Citation Subset=N)
  34 Health care administration and delivery (contribute to Citation Subset=H)
  51 Health care technology indexed by NICHSR/NLM (contribute to Citation Subset=T)
  26 History of medicine core journals indexed fully by HMD/NLM (contribute to Citation Subset=Q or QIS)

*NLM started a long-term project in July 2013 to identify indexed journals that may have ceased or for which NLM is no longer receiving data. This explains why the number of journals may decrease over time.


In the past, NLM had collaborative partners who selectively indexed some journals; those journals were not included in the MEDLINE count.

NICHSR stands for National Information Center on Health Services Research and Health Care Technology, NLM. HMD stands for History of Medicine Division, NLM.

It may be helpful to know:

  • The journal list groupings above were created for NLM in-house use, i.e., management of NLM indexing work flow.
  • A journal can belong to only one journal list.
  • These journal lists should not be confused with PubMed Subject Subsets. Subject Subsets may include citations from journals that are not part of the journal list for the same topic. For example, PubMed History of Medicine Subject Subset will not be limited to citations from the History of Medicine core journals
  • These journal lists should not be equated with PubMed Journal/Citation Subset data element (labeled as SB in the MEDLINE display format), although there is a connection between them. While a journal may belong to only one journal list, citations may be assigned multiple Citation Subset values. Every citation from a journal on a journal list will carry the Citation Subset value contributed by that journal list. Often when an Index Medicus journal fits into one of the special subject areas identified above, citations from that journal will have one Citation Subset value for Index Medicus and another Citation Subset value for the subject area. For example, British Dental Journal is an Index Medicus journal; citations from this journal have one Citation Subset value of IM for Index Medicus and a second Citation Subset value of D for Dentistry journal list. In addition, HMD and KIE, (and, in the past, NASA) may add their Citation Subset values to individual citations from any journal list title including Index Medicus journals. For example, this citation has three Citation Subset values of IM, D, and E for Ethics:

    Adewumi A, Hector MP, King JM.
    Children and informed consent: a study of children's perceptions and
    involvement in consent to dental treatment.
    Br Dent J. 2001 Sep 8;191(5):256-9.
    PMID: 11575761 [PubMed - indexed for MEDLINE]

  • Abridged Index Medicus (AIM) is a list created over 20 years ago of about 120 core clinical English language journals. It corresponds to the "Core clinical journals" subset in PubMed Limits.

For more information about journals see these resources: