Child prostitution is a significant global problem that has yet to receive appropriate medical and public health attention. Worldwide, an estimated 1 million children are forced into prostitution every year and the total number of prostituted children could be as high as 10 million. Inadequate data exist on the health problems faced by prostituted children, who are at high risk of infectious disease, pregnancy, mental illness, substance abuse, and violence. Child prostitution, like other forms of child sexual abuse, is not only a cause of death and high morbidity in millions of children, but also a gross violation of their rights and dignity. In this article we estimate morbidity and mortality among prostituted children, and propose research strategies and interventions to mitigate such health consequences. Our estimates underscore the need for health professionals to collaborate with individuals and organisations that provide direct services to prostituted children. Health professionals can help efforts to prevent child prostitution through identifying contributing factors, recording the magnitude and health effects of the problem, and assisting children who have escaped prostitution. They can also help governments, UN agencies, and non-governmental organisations (NGOs) to implement policies, laws, and programmes to prevent child prostitution and mitigate its effects on children's health.