A recent study on prison violence revealed that over 200 riots have occurred between 1900 and 1970. The magnitude and dangerousness of more recent riots have increased with overcrowded conditions. The costs of such incidents can be broken down into three areas: loss of life, property, and time. Many riots do not result in loss of life, but psychological damage to participants often occurs. Property loss costs vary greatly and can be staggering. Damage from the Attica riot of 1970 totaled over $3 million. A Select Committee on Crime listed the following problems as contributing to prison riots: poorly trained staff, rural prison location, inmate overcrowding, lack of inmate educational programs, and insufficient vocational training. Three theories have been proposed to explain riotous behavior. These include the conflict theory, spontaneous behavior theory, and collective behavior theory. Inmates and correctional officers place different emphasis on factors contributing to riots. Research into rioting reveals three important procedures that can assist in preventing riots: inmate grievance mechanisms to hear and resolve inmate complaints, use of inmate councils to communicate with prison officials, and use of attitudinal survey instruments for inmates to communicate their concerns. A photograph, tables, and 13 references are provided.