The GEDCOM format has been defined in 1987 by the Church of Jesus Christ and further developed since then. This applies to both content (the GEDCOM tags) and structure, the latter now includes includes XML.

This strengthens GEDCOM in his function as a data interchange format between different genealogy programs, which save most of the genealogical data in a separate, own format.
Example of the latter are the file formats paf (Personal Ancestral File), gno (GenoPro), ftw (Family Tree Maker) and ahn (Ahnenblatt). However, these programs are able to import and export their data to GEDCOM. Usually not all GEDCOM tags are supported.
It is impossible to give a complete overview of the GEDCOM tags at this page.
The GEDCOM specification 5.5.1 is available on GenWiki .

The example on the right demonstrates the basic structure of a GEDCOM file:
Each entry (record or record) begins with a zero (0).
The example shows entries which contain
- the head (HEAD) of the file,
- the submitter or creator (SUBM) of the file,
- the individuals (INDI)
- the relatedness to a family (FAM) and
- list of the sources (SOUR).
The entry TRLR marks the end of file.

The structure of a data set is hierarchical, the upper level (corresponding to the fields of the record) is marked with 1, this level is followed by sub item 2, etc. CONT means continuing on the next line.
The GEDCOM tags in HEAD and SUBM explain themselves and are not further explained here.
The spelling @I556@ INDI defines the individium with No. 556; the corresponding record is containing the data as known by the person\'s full name (NAME), and first name(s) (SURN and GIVN), sex (SEX), birth and death dates (with BIRT and DEAT) with sources including membership to families.
If the parents are known, then we find the family index in FAMC, as this person is a child of that family.
If this person is married an own family index (FAMS) is set, for the partner too .
CHAN refers to the date of last modification of entry, NOTE contains comments or notes.
A record defining the family (see, eg @F273@ FAM) contains information on family members, ie husband (husband) and wife (wife) with marriage date and place, here eg HUSB @I854@ and WIFE @I556@, and the children (there are three).

0 HEAD
1 SOUR PAF
2 NAME Personal Ancestral File
2 VERS 5.2.18.0
2 CORP The Church of Jesus Christ of Latter-day Saints
3 ADDR 50 East North Temple Street
4 CONT Salt Lake City, UT 84150
4 CONT USA
1 DATE 1 Feb 2010
2 TIME 19:06:17
1 FILE Desc_Chr-Schleißener.ged
1 GEDC
2 VERS 5.5
1 CHAR UTF-8
1 LANG German
1 SUBM @SUB1@
0 @SUB1@ SUBM
1 NAME hs
1 ADDR  
2 CONT  
2 CONT  
2 CONT  
2 CTRY D
0 @I556@ INDI
1 NAME Johanna Elisabeth /Weitzmann/ 
2 SURN Weitzmann
2 GIVN Johanna Elisabeth
1 SEX F 
1 BIRT 
2 DATE 13 Mar 1728
2 PLAC Friedeberg 
2 SOUR @S14@ 
1 FAMS @F273@
1 CHAN 
2 DATE 14 Aug 2002
3 TIME 01:00:00
0 @I854@ INDI
1 NAME Martin /Schleusener/
2 SURN Schleusener
2 GIVN Martin
1 SEX M
1 BIRT
2 DATE 26 Oct 1717
2 PLAC Cossin
1 DEAT
2 DATE 29 Jan 1783
2 PLAC Bärwalde
2 SOUR @S103@
1 FAMS @F273@
1 FAMC @F384@
1 NOTE Arondator.
1 CHAN
2 DATE 14 Aug 2002
3 TIME 01:00:00
0 @F273@ FAM
1 HUSB @I854@
1 WIFE @I556@
1 CHIL @I4189@
1 CHIL @I2189@
1 CHIL @I4190@
0 @S14@ SOUR
1 TITL Deutsches Geschlechterbuch, Bd...., S. 94.
0 TRLR