This article discusses the need for expert testimony and the criteria for admissibility of such testimony in child abuse cases. It addresses the scope of expert testimony in both physical and sexual abuse cases with respect to (a) descriptive and diagnostic issues, (b) witness credibility issues, and (c) legal issues. In particular, the article focuses on the admissibility of expert testimony on the battered child syndrome, the child sexual abuse accommodation syndrome, and observations of behavior with anatomically correct dolls. The article concludes that medical expert testimony is more admissible in court than mental health expert testimony.