It is an inter-Court communication between the Court situated in one country and the another situated in a different country. The procedure for issuing letter rogatory is governed by the terms of the treaty entered into between the countries. Letter rogatory is not permissible if the treaty terms do not provide for such procedure. Letter rogatory is a letter of request by one Court to another to record the evidence of witness residing within the jurisdiction of that Court. The letter rogatory is accompanied by a questionnaire. The receiving Court after summoning the witness records the answer to the questions and if the parties concerned choose to cross-examine the witness, the other Court shall permit such cross-examination. The duty of the receiving Court ends with transmitting the record of the examination of the witness.
[Ref.: Union of India v. W.N. Chadha, AIR 1993 SC 1082.]