Professional practices and decision-making procedures in investigation of child sexual abuse were studied by interviewing child protection professionals in the southeastern U.S. regarding 175 allegations of abuse. Investigation procedures used, factors associated with the decision to substantiate, and the child protection workers' degree of confidence in their decisions were recorded for each allegation. It was found that substantiated cases: (a) involved significantly older children; (b) were more likely to involve intrusive types of abuse and children of minority race; and (c) were less likely to involve a visitation or custody dispute. Characteristics of the child's disclosure served as the primary basis for substantiation decisions, although medical evidence and affective and behavioral indicators also contributed to the decisions. Case workers were less certain of their decisions when allegations involved young children and adolescents and when allegations were made in the context of custody disputes. In terms of investigatory procedures, anatomical dolls and drawings were rarely used, alleged offenders were interviewed in fewer than one quarter of the cases, and medical and law enforcement consultations were obtained at a higher rate than mental health consultations.