As a rule, children of Portuguese mother or father, born in the Portuguese territory, are Portuguese citizens.
The proof of their citizenship is made through the registration at the Portuguese Civil Register Office.
Usually, in this group there are two basic problems:
- Citizens that were born in Portugal and immigrated to another country, however their parents have not registered them in Portugal;
- Citizens that were born in Portuguese territories that no longer are Portuguese territories.
The admission of the citizenship, in both situations, is influenced by the registration of the birth at the Portuguese Civil Register Office.