More and more law enforcement agencies are using impact munitions as part of their weapons arsenals. These less-lethal devices give police the means to subdue and arrest potentially dangerous individuals and to disperse unruly crowds with less chance of injury or death to suspects, innocent bystanders, or themselves. Unfortunately, little is known about the circumstances under which impact munitions have been used or the physical effects they have on individuals in the field. This study seeks to fill that knowledge gap. What did the researchers find? A survey of law enforcement and corrections agencies yielded information from 106 agencies about 373 incidents in which impact munitions were used, with 969 projectiles fired. Impact munitions can help law enforcement officers effectively resolve potentially violent encounters in which deadly force might otherwise be used. More than 90 percent of the encounters studied were resolved without officers having to resort to lethal force. However, because impact munitions are not 100 percent effective, officers need to have deadly force available to protect themselves and others. Training in the use and handling of impact munitions is crucial to their proper use. Impact munitions need to be clearly marked so they are not confused with lethal munitions. The continuing development of improved impact munitions should further reduce the risk of death or injury to police, suspects, or others. Who should read this study? It will benefit law enforcement and corrections leaders, planners, and trainers; procurement officials; munitions manufacturers; and citizen review boards. What were the study’s limitations? Information was sought from both law enforcement and corrections agencies, but no corrections agencies are represented among the 106 respondents.