Affidavit — «аффидевит» or «письменное показание под присягой» — is a written declaration made under oath before a notary public or similar official that certain facts are true to the best of the knowledge of the person signing the document. It is widely used in arbitration and litigation when the witness cannot attend the hearing.

Russian courts admit foreign affidavits as the proof of foreign law (decision of the Supreme Commercial Court #12434/11) and, even, the proof of facts (case #А56-29235/02). Russian notaries can issue similar documents but may be reluctant to do so once the case has been opened (art. 102 of the Russian Law «On Notaries»).

This is strange as Russian courts should not admit such documents as this is directly prohibited by law (art. 81 of the Code of Commercial Procedure).