In a prospective study the number of children attending the Royal Liverpool Children's Hospital (RLCH) for examination after allegations of child abuse, and the type of abuse involved, was recorded from July to December 1990. The cost to the hospital of these examinations and initial investigations was assessed. The study was carried out in the major and minor accident and emergency departments and the Rainbow Centre of the RLCH. In six months 181 children were examined. Cases of sexual abuse and non-accidental injury were seen in equal numbers. Girls outnumbered boys and 60% were referred by social services. The costs over the six month period were 31,739 pounds. The minimum projected annual cost is 63,500 pounds. We conclude that the cost of running an effective service for the initial assessment of children who are possible victims of child abuse is considerable in practical terms and in medical time.