In the system of proving civil claims, the conflict between ordinary documents and testimony is one of the main challenges of the courts. The findings show that in Iranian law, despite the deletion of Article 1309 of the Civil Code, ordinary certified documents (Article 1291 BC) have higher probative value than testimony and the burden of proof lies with the claimant; while in the United States, documents certified by a notary public have a presumption of authenticity and testimony is only admissible if forgery is proven. The analysis of judicial practice (Unified Procedure Decision No. 12 of the Supreme Court) and comparative comparison reveal the need to amend Article 1291 of the Civil Code and create a new classification of "ordinary certified documents" as the third category of documents to clarify the superiority of certified documents over testimony.need to amend Article 1291 of the Civil Code and create a new classification of "ordinary certified documents" as the third category of documents to clarify the superiority of certified documents over testimony.