Ex parte Bain, 121 U.S. 1 (1887), was a United States Supreme Court case involving grand jury indictments.

George M. Bain, Jr. was indicted by a federal criminal grand jury and subsequently convicted for making a false report or statement as cashier of the Exchange National Bank of Norfolk, Virginia under U.S. Rev.

The Court sent the message that grand jury indictments, as required per the Fifth Amendment, would be held to a strict standard.

In 1985, upon returning to the issue of grand jury indictments in the case of United States v. Miller (1985), the Court decided on a somewhat looser interpretation of the Fifth Amendment requirements as set forth in Bain.

Now, modifications to a grand jury indictments, if only to reduce charges, make simple changes, or remove text, are allowed.