Interrogatories are written questions sent by one party to another as part of discovery–i.e. the gathering of information in preparation for trial. (The compilation of questions and the individual questions themselves may be referred to as interrogatories.) In federal courts, Federal Rule of Civil Procedure Rule 33 governs the taking of interrogatories.
Attorneys may ask anything within the scope of Federal Rule of Civil Procedure Rule 26(b), which allows discovery on “any nonprivileged matter that is relevant to any party's claim or defense and proportional to the needs of the case, considering the importance of the issues at stake in the action, the amount in controversy, the parties’ relative access to relevant information, the parties’ resources, the importance of the discovery in resolving the issues, and whether the burden or expense of the proposed discovery outweighs its likely benefit.” That is, attorneys may ask anything pertaining to facts or an application of law to facts but may not ask questions on pure legal theory. For example, in a federal court case out of Georgia, O’Brien v. International Brotherhood of Electrical Workers, the court allowed interrogatories “ask[ing] for the specific statements allegedly made by plaintiff for which he was tried. . . [and] seek[ing] an explanation as to why these statements violated these constitutional provisions.” However, it found that an interrogatory asking why a statute does not violate the constitution was a purely legal question and therefore outside the scope of Rule 26(b), and therefore impermissible as an interrogatory.
Rule 33(b) lays out additional requirements for interrogatories. It can only be responded to by a party (i.e. not a third party participating in litigation), the responding party has 30 days to respond, and the responding parties must fully answer each interrogatory. While the responding party has the possibility to object to the questions, they still must answer the interrogatories. If a party refuses to respond to an interrogatory, then the interrogating party may compel that party to respond under Rule 37(a)(3)(B)(iii).
[Last updated in December of 2020 by the Wex Definitions Team]