Gagnon v. Scarpelli, 411 U.S. 778 (1973), was the second substantive ruling by the United States Supreme Court regarding the rights of individuals in violation of a probation or parole sentence.

[1] The case involved Gerald Scarpelli, a man serving a probation sentence in the State of Wisconsin for armed robbery.

Scarpelli's probation was revoked by the Wisconsin Department of Public Welfare subsequent to his confession to police that he was involved in the burglary.

Justice Lewis Powell delivered the opinion of the court, which held that: Regarding the first part of the ruling, the probation sentence of an individual cannot be revoked without a hearing.

A determination on the status of the probation is made, and if the probationer is found in violation, a sentence (resentence) for the original criminal charge is handed down by the judge.