The Polish Code of Civil Procedure in article 1138 states that the probative value of foreign official documents is equal to Polish official documents. As a rule the law does not require legalisation to grant foreign official documents probative value equal to Polish official documents. The Code, however, provides for two exceptions to this rule which require legalisation by Polish agents or consular officers. The article presents a practical application of article 1138 of the Code on the background of regulations applicable to evidence in Polish civil procedure rules and the European Convention on the abolition of legalisation of documents executed by diplomatic agents or consular officers. The paper shows that the provision of national official documents apply, in the case of foreign official documents, only in certain instances, i.e. in some cases their direct application would not be appropriate.