Advocacy skills are required by all paediatricians concerned with the needs of the whole child, since the main presenting conditions are associated with many other factors in addition to disease: namely mental health, environment, education and social circumstances. Advocacy is required to influence these other factors. Advocacy is defined as speaking out on behalf of a child or family who has problems with the system, to improve the situation for them. The skills required for advocacy are described. Paediatricians are most often advocates in favour of individual children or their family, there is also the important field of public policy advocacy which would be carried out by an organization or group. There are many examples of advocacy in the history of child health particularly in relation to child labour. More recently, paediatricians have been advocates in relation to injury prevention and the provision of child-orientated services. Internationally, the UN Convention on the Rights of the Child is a major tool in ensuring that children's needs are met. Case examples are provided and the use of these in training paediatricians is described. Paediatricians are encouraged to make advocacy a part of their everyday working practice.