Subpoena Instanter

A subpoena instanter is a subpoena that requires immediate compliance, i.e., instantly (without delay). It is primarily used in the civil law jurisdiction of Louisiana, while the term is generally not used in common law jurisdictions other than Texas.

Administrative agencies will sometimes use an subpoena instanter to demand immediate compliance, but the Fourth Amendment typically guarantees a right to challenge such subpoenas in a court of law before being compelled to comply.