Approximately 150,000 confirmed cases of child sexual abuse were reported to child welfare authorities in the United States during 1993. This number represents about 15% of the more than one million confirmed cases of all child abuse and neglect. But the true scope of this problem is better reflected in retrospective surveys of adults, and this article summarizes data from 19 of these surveys. Considerable evidence exists to show that at least 20% of American women and 5% to 10% of American men experienced some form of sexual abuse as children. The rates are somewhat lower among people born before World War II, but there is little evidence of a dramatic increase for recent generations. The studies provide little evidence that race or socioeconomic circumstances are major risk factors. They do show elevated risk for children who experienced parental inadequacy, unavailability, conflict, harsh punishment, and emotional deprivation. Adult retrospective studies are also good sources of information about the characteristics of abuse. Most sexual abuse is committed by men (90%) and by persons known to the child (70% to 90%), with family members constituting one-third to one-half of the perpetrators against girls and 10% to 20% of the perpetrators against boys. Family members constitute a higher percentage of the perpetrators in child protective agency cases because the mandate of these agencies generally precludes their involvement in extrafamily abuse. Around 20% to 25% of child sexual abuse cases involve penetration or oral-genital contact. The peak age of vulnerability is between 7 and 13. Studies of the criminal justice processing of sexual abusers suggest that, compared with other violent criminals, slightly fewer are prosecuted, but of those prosecuted, slightly more are convicted. Studies conducted in the 1980s also showed that, once convicted, relatively few sexual abusers receive sentences longer than one year, while 32% to 46% serve no jail time. Overall, there is little evidence to suggest that either the child welfare system or the criminal justice system abandons its usual standards of operation and acts hysterically when confronted with sexual abuse.