Your Dutch tax identification number

BSN: Citizen Service Number (successor of the sofi number)


Last modified: 01 December 2013


What is a citizen service number?


The citizen service number - in Dutch written as Burgerservicenummer or BSN - is a unique personal ID number of every citizen who is registered in the population register (Municipal Personal Records Database) at the municipal authorities. The citizen service number is the successor to the ‘SoFi’ number. The citizen service number will be used by all government organisations.


When am I entitled to a citizen service number?


When you are registered in the population register (Municipal Personal Records Database) with the municipal authorities, you will automatically obtain a citizens service number.


How do I obtain a citizen service number?


On November 26, 2007 the sofi number of everyone who was registered in the population register (Municipal Personal Records Database) at the municipal authorities has been automatically converted into a citizen service number. From that date, everyone registering with the municipal authorities will be given a citizens service number. You will notice this, for example, if you register your new-born child with the municipality. People who have a sofi number, but are not registered with the municipal authorities, will keep their sofi number. People who will not be registered in the Netherlands since they are living outside the Netherlands will have to contact the tax authorities for foreign residents in Heerlen to get a sofi number.

Examples of questions answered in our Knowledge Base:

Why was a new number system introduced?


The citizen service number makes it easier and more reliable to handle personal data by the government. It was necessary to replace the sofi number by the citizen service number because the sofi number was not capable anymore to fulfil its task. The legal, technical and organisational conditions for making, issuing and using the number have been completely renewed.

Which organizations use the citizen service number?


The citizen service number legislation covers that all governmental bodies can use the citizen service number when executing their task. Certain arrangements can be made by the legislation of the citizen service number so non-governmental bodies can use the citizen service number. This means that, for example, employers will have to use the citizen service number for the purpose of supplying income data to the tax authorities. General practitioners or family doctors and other medical organizations will use the citizen service number when the legislation on the citizen service number in the medical field has been implemented. 

The general rule is: when an organisation does not have the need to store your personal data, including the citizen service number, in order to fulfil a duty, the organisation is not allowed to use or store your citizen service number.

Can any company use my citizen service number?


That depends. If you work for the supermarket, as your employer the supermarket is required to exchange information on your earnings with the tax authorities using your citizen service number. The supermarket is not permitted to use it for any other purpose unless there is a specific legal basis. Under the current proposal the supermarket would not be permitted to do so even with your permission.

Will all my data be collected in one place?


No. It will remain the case, for example, that the tax authorities will manage the data on you that it needs to issue tax assessments. The UWV will manage the data needed to administer the unemployment insurance scheme. The municipal social security department will manage the data needed to administer the social security benefit system. 

The aim, however, is to concentrate the recording of certain key data and make it available to all government bodies. This is already the case with the key data in the population register, which municipalities collect for all the government agencies that need it. There will also be other ‘key registers’, e.g. one containing data on taxable income, which will provide other government bodies needing that data in order to do their work with a reliable source. There will be separate legislative processes for the various key registers. The citizen service number system will facilitate an effective and errorless exchange of information with these.

Will every government department know everything about me?


No. What data a government body is permitted to process is laid down not in the citizen service number legislation but the Personal Data Protection Act and sector-specific legislation. In a nutshell, as a rule a government body is only permitted to ‘know’ the data it needs to do its work. If you apply for a building permit, the municipal authority does not need to know whether you have any outstanding speeding fines, so it is not permitted to obtain that information.


If someone knows my citizen service number, does that give him access to all my data, for example my medical records?


No. A citizen service number does not in itself confer any rights, either to the holder of that citizen service number or to someone producing it. In other words, the citizen service number is not a key that provides the right of access to a database.

In practice, access to the data would involve circumventing the database protection system. The Personal Data Protection Act lays down that personal data must be properly secured against unauthorized access. What this proper protection involves depends on the circumstances. Some data collections are public (e.g. the public registers of the land registry); others are subject to very strict access rules (police files, medical records). The Act lays down that the security arrangements must be in line with the risks and the state of the art. Anyone who is responsible for a collection of personal data must install a security system that only permits access to authorized persons. 

A government body that is authorized to access certain data in a collection it will use the citizen service number as an aid, thus improving efficiency and reliability.

Will the introduction of the citizen service number increase the risk of identity fraud?


Unlike the sofi number system, the citizen service number will make identity fraud more difficult. Identity fraud is where someone pretends to be another person, e.g. by using someone else’s citizen service number, usually with gain as the motive. The citizen service number system has better safeguards against this kind of abuse than the sofi number system. The number issuing system is better, preventing the issue of more than one number to the same person. Citizen service number users will have to match the person to the citizen service number before processing data. The citizen service number system provides facilities to assist users with matching (the citizen service number management facility).


Who can I turn to if there is something wrong with my citizen service number?


In a word, (1) the government agency where the error has occurred; (2) if there is something wrong with your key data, including your citizen service number, your municipal authority. 

In most cases what you will run up against will not be a ‘mistake in the citizen service number ’ but having to pay more tax than you expected or not being granted a licence, permit or allowance. There are various steps you can take against the government body that has issued the assessment or refused to grant your application. You can appeal against the assessment or refusal, ask the body to correct the data it is using, or complain to the body about the treatment you have received. 

If the dispute is related to key data in the population register which you believe to be incorrect, e.g. an incorrect citizen service number, you can ask your municipal authority to correct it. Decisions will have to be made based on the correct data. If your appeal or request for correction does not produce the desired results, you can lodge a complaint with the courts. In most cases you can appeal against the court’s decision in a higher court. 

In case the mistake or complaint is not addressed in time or incorrectly by the organisation (appealing body), you can contact the citizen service number point. 

Disputes about treatment can be placed to the National Ombudsman. In the event of a dispute about the processing of your personal data you can ask the Dutch Data Protection Authority (Cbp, College bescherming persoonsgegevens) to advise or mediate. 

To sum up, the options open to you are:

  1. appealing to the body concerned
  2. requesting a correction
  3. complaining about your treatment
  4. lodging a complaint with the courts
  5. appealing against the court decision
  6. Citizens Service Number point
  7. lodging a complaint with the national or local ombudsman
  8. asking the Cbp to advise or mediate.




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