The literature on violence by psychiatric inpatients provides some evidence that rates of violence may be increasing over time and that they are higher in the United States than in other nations. This review examines the extent of inpatient violence and describes the individual, situational, and structural factors with which it is associated. Individual factors include acute illness, psychosis, drug abuse, age, and history of violence. Situational variables include overcrowding, provocation, staff inexperience, and management tolerance of violence. Structural factors include changes in mental health policy that have made dangerousness a frequent criterion for commitment and a shortage of treatment resources. The author concludes that violence is the result of an interaction between the various types of factors and is not simply an expression of individual pathology.