Payroll Pitfall nr 2 : Limosa and Dimona

Limosa (

Written by Xavier Norman


A Limosa declaration and a Dimona declaration are mandatory electronic notifications for every employer. Prior to the start of an employee, the employer must declare its employees with an electronic notification system to the Belgian National Social Security Office (NSSO). Employers familiar with the Belgian administration can handle these declarations on the website of the National Social Security Office (NSSO). In practice, most employers rely upon the expertise of a Belgian payroll provider.


What is a Limosa declaration?

Limosa stands for “Landoverschrijdend Informatiesysteem ten behoeve van Migratie Onderzoek bij de Sociale Administratie” and can be translated as cross-country information system for migration research at the social administration.

Limosa declaration Belgium (

Employers assigning foreign employees temporarily or partially to Belgium must notify the National Social Security Office (NSSO) about the assignment before the employee arrives in Belgium. This requirement is called a Limosa declaration.

Posted workers from a European Economic Area (EEA) state and Switzerland, to Belgium, remain under the social security system of their home country, and are exempt from Belgian social security. Posted workers must be able to present proof of the Limosa declaration at any moment to the social inspectorate.

There are some exemptions from this notification requirement, e.g. for employees attending short-term business meetings (i.e. meetings of up to 20 consecutive calendar days, with a total maximum of 60 days per year).

This is an important notification. Failure to make Limosa declaration exposes Belgian and foreign employers to criminal sanctions. Not filing a Limosa-declaration or filing this declaration too late, can lead to a criminal fine, going from € 24.000 up to € 576.000 per employee.

What is a Dimona declaration?

Dimona is an acronym for “Déclaration Immédiate/Onmiddellijke Aangifte” that means immediate declaration of employment to the National Social Security Office (NSSO).

Dimona National Social Security Office - NSSO ( employee entering or leaving employment for an employer must be registered electronically to the National Social Security Office (NSSO) via a Dimona declaration. It is obligatory for all Belgian and foreign employers, including government departments.

The electronic notification is linked to an electronic staff registry in which employees are listed chronologically by employment start dates.

In case you are hiring a new employee, these formalities must be done prior to the first effective working day. Don’t forget this, because failing to comply with the Dimona formalities might result in a criminal fine going from € 2.400 to € 24.0000 and an additional contribution (“fine”) from the National Social Security Office (NSSO). The amount for 2020 is set at € 2.949,39 per employee.

Most employers give mandate to a payroll provider to fulfill its administrative obligations related to Dimona and Limosa.


What are other payroll pitfalls for employers in Belgium?

Have a look at our posts Payroll Pitfall nr 1 : Umbrella Company and Employer of Record and Mandatory work regulations for employees: Payroll Pitfall nr 3.


  1. For employees subject to the social security system of a foreign country and who are exempt from Belgian social security, a Limosa declaration is required
  2. If you want to be compliant with Belgium legislation, don’t forget to handle the Dimona declaration for employees subject to Belgian social security
  3. Be sure to contact your payroll provider in due time allowing them to arrange the mandatory registration in Belgium

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