The legalization of original academic documents in order to ensure their validity in Spain is an internationally agreed process which requires the prior recognition of signatures by the corresponding Spanish and foreign authorities.

Nonetheless, for the countries that signed the Hague Convention of 5 October 1961, a simplified procedure is in force.

With the Apostille of The Hague a country that is a signatory of The Hague Convention recognizes the legal validity of a public document issued in another country that is a signatory.

This procedure, which must be carried out in the country where the document was issued, consists in adding to the document an apostille that certifies the authenticity of public documents issued in another country. The countries that are signatories thus recognize the authenticity of documents issued in other countries that accept the apostille.