This thesis deals with the issue of documents as evidence in international arbitration. The work is divided into 7 main parts, excluding the introduction, the conclusion, the bibliography and the statement of originality. The general notion of arbitration and international arbitration is considered first. It then approaches the narrower issue of evidence in arbitration with special emphasis on the authority of the arbitral tribunal when deciding on the admissibility, relevance and probative value of the proposed and presented evidence. In that regard, it is necessary to distinguish between the authority of the court towards the parties in the proceedings and towards all third parties who do not participate in the proceedings. The sources of documents as evidence in international arbitration are also discussed, with special emphasis on the IBA Rules and the Prague Rules as the arbitration rules that most extensively regulate the use of documents. This work focuses mainly on the procedure for obtaining documents from the parties themselves, the form and manner in which the request for documents is submitted, the admissibility of the documents themselves and the sanctions for failure to provide them. Finally, some issues are analyzed when proving documents, such as proving with electronic documents and the translation of documents.