To determine how often children falsely report being sexually abused, this study asked professionals to indicate the percentage of children with whom they had worked who had made false reports. In addition, this study examined the variables that might be associated with the percentage of false allegations reported by professionals. The factors examined were age of the child, profession of the interviewer (law enforcement versus mental health), expectation of the interviewer (whether they believe children generally do not lie about sexual abuse versus interview children neutrally), and sex of the interviewer. Boston-area professionals, including 74 law enforcement professionals and 127 mental health professionals, were interviewed by telephone. The results indicated that women reported a smaller percentage of false allegations than did men, and that all professionals reported fewer false allegations for children under 6 than they did for children age 6-9 or 10-12. An age-of-child X profession-of-interviewer interaction indicated that the law enforcement and mental health professionals were differentially affected by children ages 10-12. Mental health professionals reported a significantly higher percentage of false allegations than did law enforcement professionals. The results of this study indicated that professionals reported a small percentage of cases as having been false. The results also indicated that the percentage of false reports was related to the sex of the interviewer, age of the child, and profession of the interviewer. (BHK)