Most child victims will be in acute and serious emotional crisis when brought to the physician, may be infected with venereal disease, and manifest behavioral problems. Disclosure of incest following a first incident is rare, and such behavior in most cases has been occurring for months or years before discovery. Skillful assessments in child sexual abuse cases demand time, special interviewing skills, facility with pediatric and adolescent gynecologic examination, understanding of the psychodynamics of sexual abuse and incest, and knowledge of legal requirements in such cases. Guidelines for interviewing the mother suggest moving from the least sensitive topics to the most sensitive, focusing on family functioning and situations related to sexual activity. The physician's interview with the child should contain four phases: establishing a relationship, eliciting general personal information, eliciting details of sexual activity, and preparation for the physical examination. The latter should concentrate on the skin, mouth, abdomen, genital, and rectal areas. Necessary diagnostic studies include evaluations for gonorrhea and syphilis and presence of sperm or semen, pregnancy tests, urinalysis, collection of forensic material, and radiologic bone survey. The author lists diagnostic indicators of possible child sexual abuse and discusses the physician's actions following the evaluation, such as reporting, preventing venereal disease, referrals, and medical followup. The paper supplies eight references.