Duhaime's Law Dictionary

Interrogatories Definition:

Pre-trial numbered and written questions on relevant matters to the litigation, sent to the other side of litigation, and for which reply is mandatory.

In order to assist the parties to litigation in preparation for trial, the courts have developed a series of pre-trial discovery tools, such as examination for discovery, discovery of relevant document, and the set of written questions put to the other side and which require written replies, usually in affidavit form.

Interrogatories are the most unused, and least known tool of civil litigation. Indeed, most self-represented parties are not even aware of the Court rules which extend this opportunity. Many lawyers plod through complex civil cases without ever reaching for this invaluable tool.

The mechanics and deadlines differ from jurisdiction but the general framework remains the same. One side to litigation delivers to the other a set of numbered questions on relevant issues. The other side then has a set number of days to reply; for example, three weeks, and the reply must be in affidavit form. The timing of a demand by way of interrogatories is important - it generally can only come after a statement of defence has been filed, and it cannot occur on the eve of trial.

Interrogatories, as with examinations for discovery, is to obtain admissions which would either defeat the other side's case in whole or in part or, in any event, expedite trial.1 But while the transcript of an examination for discovery is generally available at trial only to impeach a witness, replies to interrogatories can be filed with the court and readily used at trial.

In 1914, the English Court of Appeal wrote in Marriot:

"The law with regard to interrogatories is now very sweeping. It is not permissible to ask the names of persons merely as being the witnesses whom the other party is going to call, and their names not forming any substantial part of the material facts; and I think we may go so far as to say that it is not permissible to ask what is mere evidence of the facts in dispute, but forms no part of the facts themselves. But with these exceptions it seems to me that pretty nearly anything that is material may now be asked. The right to interrogate is not confined to the facts directly in issue, but extends to any facts the existence or nonexistence of which is relevant to the existence or nonexistence of the facts directly in issue."

There are some limits to interrogatories such as the individual to whom it is directed must have personal knowledge or have access to an answer within reasonable inquiries.

Note also these words of Justice Langdale in Lincoln v Wright:

"All interrogatories must, to some extent, make a suggestion to the witness. It would be perfectly nugatory to ask the witness if he knew anything about something."


  • Duhaime, Lloyd, Civil Litigation Law
  • Lincoln v Wright, 4 Beav. 166, at 171 (1841)
  • Marriott v. Chamberlain, (1886), 17 Q.B.D. 154. Quoted with approval in Osram Lamp Works Ltd. v. Gabriel Lamp Co., [1914] 2 Ch. 129 (Eng. C.A.) and in Nicolay v. George 16 C.P.C. (4th) 5 (BCSC, 1995)
  • Twitchell v Delta Hotels, 9 B.C.L.R. 204 and also at 95 D.L.R. (3d) 662 (BCSC, 1979; note 1)

Categories & Topics:

Always looking up definitions? Save time with our search provider (modern browsers only)

If you find an error or omission in Duhaime's Law Dictionary, or if you have suggestion for a legal term, we'd love to hear from you!