Young people, especially inner-city youth, have become inured to and traumatized by violence. Law enforcement and public health officials report a virtual epidemic of youth violence in both inner cities and suburbs. Much of the violence is found in poor neighborhods where a disproportionate number of victims and perpetrators live together. According to the Federal Bureau of Investigation, more than 2,200 murder victims in 1991 were under 18 years of age. The Justice Department estimates that nearly a million young people between 12 and 19 years of age are raped, robbed, or assaulted each year, often by their peers. The effects of violence, however, cannot be measured by official statistics alone. The true extent of death and injury due to violence is probably much higher than data indicate. Studies demonstrate a casual attitude toward violence that is most acute in inner-city neighborhoods where normal behavior rules do not apply and young people do not have traditional social supports. In addition, drugs play a significant role in the incidence of violent crime in urban communities where a "street mentality" prevails. The role of aggression in the violent behavior of youth is discussed.