In the face of the denials of perpetrators, investigators must typically depend on children's accounts or physical and material evidence in order to determine whether allegations of sexual maltreatment are valid. Much of the physical evidence available to investigators is obtained from the medical examination of young victims. Considerable progress has been made in the last decade in the evaluation of genital and perianal injuries. Regarding behavioral indicators of sexual abuse, no specific behavioral syndromes characterize victims of sexual abuse. Sexual abuse involves a wide range of possible behaviors that appear to have widely varying effects on its victims. The absence of any sexualized behavior does not confirm that sexual abuse did not occur any more than the presence of sexualized behavior conclusively demonstrates that sexual abuse occurred. In interviews with alleged child victims, the most reliable and accurate information is obtained from children who are responding to open-ended questions designed to elicit free narrative accounts of events that they have experienced. Dolls and other props are useful for various purposes in interviews with child victims. The concluding section of the article identifies areas that need further investigation. 20 references