It is a registration number for employment and social security, it is actually the insurance identification of all citizens and it is mandatory for everybody.
All the persons who reside permanently in Greece regardless if they are Greek or foreigners, have the right to obtain SNN.
SSN is mandatory for everyone who is insured (directly or indirectly), who is employed or is about to do so, who are pensioners or who receive unemployment benefit. It is also necessary in order to have access to hospital and medical healthcare of the public health services.
You are required to visit Citizen Service Centre of your residence. You can do so in person or another person on your behalf that will have the authorization notarized by your signature. The authorization of such document can be done either at a Citizen Service Centre or a Police Station.
-you have to present the original proof and submit a photocopy of your legal residence in Greece (asylum applicant’s card, residence permit, passport, Identity Card, visa, etc.)
-if you do not have in possession any of the above documents, you may be asked to present a family status certificate translated in Greek
-a birth certificate is needed for minors that were born in Greece
On the same day that you will submit the necessary documents, they will be examined by an employee who will issue an SSN if your documents are found complete.