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OLDMEDLINE represents journal article citations from two printed indexes: Cumulated Index Medicus (CIM) and the Current List of Medical Literature (CLML). Created by the National Library of Medicine, these approximately 1,816,000 citations to articles from international biomedical journals cover the fields of medicine, preclinical sciences and allied health sciences from 1949 through 1965. OLDMEDLINE records, most of which are included in the MEDLINE database, can be searched via PubMed® or the NLM Gateway.


In 1964, NLM began using the computerized MEDLARS® (Medical Literature Analysis and Retrieval System) system as a mechanism for producing Index Medicus® (IM). In 1971, MEDLARS went online with the introduction of MEDLINE®, an interactive searchable database of data from the 1966 Index Medicus forward. The 1964 and 1965 issues of Index Medicus, while available in electronic form, were not included in MEDLINE because of format differences. In the mid-1990s, NLM was assisted in its effort to provide online access to these older citations by the Deutsches Institut fur Medizinische Dokumentation und Information (DIMDI), the International MEDLARS Center in Germany. DIMDI had tapes of the original data from the 1964 and 1965 Cumulative Index Medicus, which they had converted and then supplied to NLM to create OLDMEDLINE in 1996. The citations from the 1960 - 1963 CIM and the 1949 - 1959 Current List of Medical Literature were converted from print copy into machine-readable form.


Date Added Citations Added Printed Index
December 1996 153,127 1965 CIM
153,196 1964 CIM
November 1998 233,654 1962 - 1963 CIM
227,897 1960 - 1961 CIM
July 2000 106,301 1959 CLML
113,273 1958 CLML
May 2002 103,427 1957 CLML
May 2003 105,757 1956 CLML
109,778 1955 CLML
107,927 1954 CLML
103,502 1953 CLML
February 2004 89,557 1952 CLML
97,332 1951 CLML
September 2004 55,850 53,533 citations from 1950 CLML
2,317 citations from 1951 - 1965*
December 2007 55,557 1949 CLML

*In order to load OLDMEDLINE data into PubMed, each citation must be linked to a parent serial record in LocatorPlus. Determining the proper link for some of these older citations takes research time which can result in the citations being made available later than the online debut date for the majority of a year's index. Research and user reports also uncover gap issues that NLM adds and citations that are duplicates that NLM deletes; these changes are not reflected in the counts given in the chart.

NLM® expects to continue converting citations from its older printed medical indexes to machine-readable form and to add these citations to PubMed's OLDMEDLINE subset as time and resources permit.

Data Quality

OLDMEDLINE records have been created using standards that are different from the data entry standards for MEDLINE records. There are also variations among OLDMEDLINE citations in the data elements (fields) present in the citation as well as in their format, depending on the original source from which the citations were obtained. For details, see the individual MEDLINE/PubMed Data Element (Field) Descriptions.

OLDMEDLINE citations lack the individual and accumulated changes and improvements that have been made to data in other NLM files during annual file maintenance. Certain fields may contain outdated or erroneous data and the data are not cosmetically consistent from year to year (e.g., the use of upper/lower case). The citations basically reflect the contents of the original printed indexes that were produced under policy and procedures of the time. The exceptions to this are that NLM has identified and updated the Journal Title Abbreviation and added the current ISSN. Each OLDMEDLINE citation is linked to a parent serial record in NLM's online catalog LocatorPlus. In addition, beginning with 2005 Year-End Processing, OLDMEDLINE citations with MeSH headings (see MeSH Mapping Project ) are included in the individual and accumulated changes and improvements that are made to the NLM data during annual maintenance, notably changes to the Medical Subject Headings (MeSH®) vocabulary.


Note the following aspects of OLDMEDLINE citations when searching:

Lack of Abstracts

When searching OLDMEDLINE citations, it is important to remember that the absence of abstracts affects subject retrieval.

Original Subject Headings

To distinguish the original subject headings from the printed indexes from current MeSH, all original subjects have been placed in the Other Term [OT] field of OLDMEDLINE records in PubMed. Note the following characteristics of these subject headings:

  • Few subject headings (approximately 3 - 5 per citation). See the Sample Record One, below. The 1964 and 1965 citations tend to have more subject headings (approximately 3 - 8 per citation). See the Sample Record Two, below.
  • "Check tag" headings (e.g., ANIMALS, CHILD, INFANT) applied inconsistently and should not be used to search.
  • Original subject headings have not been updated, and may not match current MeSH vocabulary.
  • Subheading practice varied:
    • No subheadings on 1963 - 65 CIM citations and 1950 and 1951 CLML citations.
    • Various subheadings on 1960 - 62 CIM citations and 1949, 1952 - 59 CLML citations.
  • All headings designated as major topic.

Because these original subject headings are not current MeSH, the subject headings in the [OT] field of OLDMEDLINE citations do not relate to current hierarchical MeSH Tree numbers, and the MeSH search capabilities (i.e., "explosions") that collect indented (more specific) terms are not functional for these data in the OT field.

MeSH Mapping Project

NLM has begun an OLDMEDLINE OT subject heading-to-MeSH Heading mapping project. This project maps the original subject headings assigned to the citations when they appeared in the print indexes to the current MeSH vocabulary. NLM estimates that approximately 93% of the OLDMEDLINE citations have at least one current MeSH Heading (89% of the original subject headings have been mapped), and will, therefore, be retrieved by PubMed searches that incorporate MeSH headings/explosions. Approximately 73% of the headings and subheadings were a one-for-one match done by machine. The other 16% were mapped after a review by NLM staff. The original subject headings are being retained in the OT field.

Please note that all current MeSH Headings added to OLDMEDLINE records have been added as Major MeSH Headings because 13 of the 15 years of data have only headings under which the citations appeared in the print indexes. However, two years of data, the 1964 and 1965 CIM, contain additional MeSH Headings that do not represent the major point of the article yet are also set to Major status because the original distinction between major and not major had been lost over the years during various conversion efforts and NLM did not have the resources to restore that distinction. Remember, as explained above, that OLDMEDLINE citations have MeSH headings such as the commonly used check tags for Animals, Age groups, etc. applied inconsistently and that the subheading practice varied greatly over the years.

As of late 2006, citations from the OLDMEDLINE print index sources that have had all of their original subject headings mapped to current MeSH carry the status tag [PubMed - indexed for MEDLINE] (see Sample Record Two, below). A search for medline [sb] in PubMed will include these records. Citations that have not had all of their original subject headings mapped to current MeSH will have the status tag [PubMed - OLDMEDLINE] (see Sample Record One, below). A search for oldmedline [sb] will identify these records. Citations digitized in the future from earlier years of the print index CLML will be entered in PubMed with the citation status of [PubMed - OLDMEDLINE] until their original subject headings are completely mapped to current MeSH. Once this mapping is completed, these records will be designated as MEDLINE records and their citation status will become [PubMed - indexed for MEDLINE].

To search for all citations that originated from the OLDMEDLINE print index sources, regardless of their status, search jsubsetom in PubMed.

Also, see the articles OLDMEDLINE Citations Join PubMed. NLM Tech Bull. 2003 Sep-Oct; (334):e2 and Changes to OLDMEDLINE Records - Status Tag Change. NLM Tech Bull. 2006 Sep-Oct; (352).


OLDMEDLINE records are included in PubMed available free of charge at

Document Delivery

All articles cited in PubMed, including those in the OLDMEDLINE subset, can be ordered using Loansome Doc®.

Sample Record One: PubMed Summary display format for a 1955 OLDMEDLINE citation

[Analysis of liver glycogen in normal and diabetic rats with ultracentrifuge.]
Biochem Z. 1955;327(1):32-8. German. No abstract available.
PMID: 13260233 [PubMed - OLDMEDLINE]

Sample Record One: PubMed MEDLINE display format for a 1955 OLDMEDLINE citation

PMID- 13260233
DA - 19561201
DCOM- 20030501
LR - 20051116
PUBM- Print
IS - 0366-0753 (Print)
VI - 327
IP - 1
DP - 1955
TI - [Analysis of liver glycogen in normal and diabetic rats with
PG - 32-8
LA - ger
PT - Journal Article
TT - Analyse von Leberglykogenen normaler und diabetischer Ratten mit der
PL - Not Available
TA - Biochem Z
JT - Biochemische Zeitschrift.
JID - 15540070R
RN - 9005-79-2 (Glycogen)
MH - Glycogen/*metabolism
MH - Liver/*metabolism
OID - CLML: 5629:12147
OT - *DIABETES MELLITUS/experimental
OT - *GLYCOGEN/metabolism
OT - *LIVER/metabolism
EDAT- 1955/01/01
MHDA- 1955/01/01 00:01
PST - ppublish
SO - Biochem Z. 1955;327(1):32-8.

Sample Record Two: PubMed Summary display format for a 1965 MEDLINE citation that originated from OLDMEDLINE

J Forensic Sci. 1964 Oct;9(4):485-91. No abstract available.
PMID: 14226373 [PubMed - indexed for MEDLINE]

Sample Record Two: PubMed MEDLINE display format for a 1965 MEDLINE citation that originated from OLDMEDLINE

PMID- 14226373
DA - 19650301
DCOM- 19961201
LR - 20061103
PUBM- Print
IS - 0022-1198 (Print)
VI - 9
IP - 4
DP - 1964 Oct
PG - 485-91
LA - eng
PT - Journal Article
TA - J Forensic Sci
JT - Journal of forensic sciences.
JID - 0375370
RN - 0 (Blood Glucose)
RN - 50-99-7 (Glucose)
MH - *Autopsy
MH - *Blood Glucose
MH - *Diabetes Mellitus
MH - *Forensic Medicine
MH - *Glucose
MH - *Laboratory Techniques and Procedures
MH - *Pathology
MH - *Vitreous Body
EDAT- 1964/10/01
MHDA- 1964/10/01 00:01
PST - ppublish
SO - J Forensic Sci 1964 Oct;9(4):485-91.

Further Information

For information about OLDMEDLINE data or other NLM services, contact:

Customer Service
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8600 Rockville Pike
Bethesda, MD 20894
Telephone: 1-888-FINDNLM (1-888-346-3656) or (301) 594-5983

Last reviewed: 08 January 2008
Last updated: 08 January 2008
First published: 05 May 2003
Metadata| Permanence level: Permanence Not Guaranteed