At the beginning of a jury trial, both parties to the case may be required to submit a list of prospective witnesses. In a criminal case, it may be used to inform prospective jurors of who will likely testify, thus allowing prospective jurors to state if they know any of the witnesses and would therefore possibly be partial. However, disclosure of witness names can be subject to a protective order.
If either party desires the testimony of a given witness, that party must take the appropriate steps to obtain the witness’s presence at an appropriate time and in an appropriate fashion, and no party should assume a given witness will be produced by the other side simply because that witness’s name appears on the witness list, or has previously been identified as a potential or likely witness. Failure to include a witness on the required witness lists may result in that witness' testimony being prohibited at trial, or other sanctions. Court rules vary, so requirements in your jurisdiction should be consulted.
A supplemental witness list is obligated to be exchanged if any additions or changes are made to the originally supplied list.
The following is an example of a federal law governing witness lists:
"§ 13.22 Exchange of witness lists, statements, and exhibits.
- At least 15 days before the hearing or at such other times as may be ordered by the ALJ, the parties shall exchange witness lists, copies of prior statements of proposed witnesses, and copies of proposed hearing exhibits, including copies of any written statements that the party intends to offer in lieu of live testimony in accordance with § 13.33(b). At the time the above documents are exchanged, any party that intends to rely on the transcript of deposition testimony in lieu of live testimony at the hearing, if permitted by the ALJ, shall provide each party with a copy of the specific pages of the transcript it intends to introduce into evidence.
- If a party objects, the ALJ shall not admit into evidence the testimony of any witness whose name does not appear on the witness list or any exhibit not provided to the opposing party as provided above unless the ALJ finds good cause for the failure or that there in no prejudice to the objecting party.
- Unless another party objects within the time set by the ALJ, documents exchanged in accordance with paragraph (a) of this section shall be deemed to be authentic for the purpose of admissibility at the hearing."