The courts have held that correctional officers may use force to enforce discipline and protect themselves and others. The use of force, however, must be reasonable under the circumstances. In addition, the U.S. Supreme Court has determined that correctional staff may be liable for failing to prevent harm to an inmate by another inmate if it can be shown that the officer's conduct displayed "deliberate indifference" to the safety of the inmate. Jail personnel may lawfully use force against inmates in one of four situations: in self-defense, in defense of others, to enforce rules and regulations, and to prevent criminal activity within the institution. This article also discusses what constitutes "reasonable" force and the standard of review in use-of-force cases. Another section of the article summarizes the results of a survey sent to the administrators of a sample of large U.S. jails. The survey focused on various aspects of the use of force, including use-of-force policy provisions, use-of-force training, and use-of-force incident reporting. 4 tables and 6 references