Declarations of legal cohabitation

Legal cohabitations down by 3.6% in 2023

Legal cohabitations down by 3.6% in 2023

In 2023, 36,990 declarations of legal cohabitation were registered in Belgium, i.e. a decrease of 3.6% compared to the previous year. There is a certain regional homogeneity here:  -3.1% in the Walloon Region, -3.2% in the Brussels-Capital Region and -3.9% in the Flemish Region.

The age at first partnership is increasingly high. Legal cohabitants who have never been married have an average age of 31.9 years for the first partner and 30.1 years for the second[1].

As for terminations of legal cohabitation, they remain relatively stable: -0.4% at national level, +2% in the Brussels-Capital Region, -0.2% in Flanders and -0.9% in Wallonia. The average duration of legal cohabitations that have been terminated continues to increase: it amounts to 5.9 years. In 2023, legal cohabitations giving way to marriage still account for more than half of all terminations (56.5%). This phenomenon is more marked in Flanders (61.1%) than in Wallonia (49%) or Brussels (44.2%).  

Legal cohabitation has been open to same-sex couples since it was introduced in 2000. These couples accounted for 14.7% of declarations of unrelated partnerships in 2000 and 6.4% in 2003. This proportion has now stabilised at around 4% for the past 4 years.

[1] The first partner is the man or the oldest partner for same-sex couples; the second partner is the woman or the youngest partner for same-sex couples.

Table 1

Evolution of the number of legal cohabitation declarations per year and administrative unit, since 2000

Administrative unit Year
2000 2005 2010 2015 2020 2023
Belgium 2,694 15,513 36,962 40,770 36,329 36,990
Brussels-Capital Region 121 1,594 2,957 3,125 2,790 3,037
Flemish Region 2,040 7,569 21,928 23,335 21,457 22,281
Walloon Region 533 6,350 12,077 14,310 12,082 11,672
Table 2

Evolution of the number of legal cohabitation terminations per year and administrative unit, since 2000

Administrative unit Year
2000 2005 2010 2015 2020 2023
Belgium 111 3,299 13,487 22,227 21,845 28,957
Brussels-Capital Region 5 271 909 1,340 1,283 1,610
Flemish Region 83 1,909 7,779 13,326 13,285 17,313
Walloon Region 22 1,039 4,472 7,099 7,133 9,700

Statbel publishes for the first time this year a statistic on the declaration of legal cohabitation using the National Register of Natural Persons (RNPP). According to the law of 23 November 1998 establishing legal cohabitation (published in the Belgian Official Journal on 12 January 1999), two persons living together have the possibility, since 1st January 2000, to officially confirm the fact that they live together. Therefore, there is legal cohabitation when two persons living together make a declaration to this effect to their local authorities, irrespective of their sex and relationship. The conditions for such a declaration are the following:

  • having the legal capacity to enter into a contract
  • not being married
  • not being in a legal cohabitation with another person The civil registrar is required to verify compliance with the legal conditions and to register the declaration in the RNPP.

In Belgium, legal cohabitation refers in principle to a situation where two persons live together. However, we have been able to detect some rare cases of registration of legal cohabitation through consular offices abroad.

The current statistic is produced using the information type “legal cohabitation” (I.T. 123) of the RNPP. The I.T. 123 registers a series of data relating to legal cohabitation, including the date of the declaration, the place of registration of the declaration (municipality of residence), the presence of a notarial contract (with the date and place of signature), the date and the reasons of termination. By coupling this information with other I.T. in the RNPP, we can characterise the cohabitants and create tables based on the sex, the age, the nationality, etc. A foreigner residing illegally on the territory can legally enter into legal cohabitation provided that he/she, together with the person with whom he/she is living, has a common principal residence in Belgium.

However, this statistic does not include any cases of two persons living together who are registered in the waiting register. In order to get a coherent statistic, we also have excluded some rare cases where there is a contradiction between the civil status and the situation of legal cohabitation (clearly married (or divorced) persons based on a “reasonable” observation period; cases related to a late - but “reasonable” - registration of divorces are therefore included in the statistics).