No child should be denied immunisation without serious consideration given to the consequences. In the past, many contraindications to vaccination were based on theoretical concerns. These concerns often assumed an immunoallergic mechanism for adverse reactions, whereas many such events are often due to other causes. Other contraindications were based on evidence of excess risk, but this risk was not always balanced against the higher risk of disease. Therefore, contraindications often varied between countries and over time. In recent years, the widespread availability of less reactogenic vaccines and the common use of combined preparations have prompted a review of contraindications in many countries. Accumulated experience worldwide has allowed the list of conditions that contraindicate vaccination to be reduced. The international consensus now is that there are very few situations in which a child should not be immunised and the only true contraindication applicable to all vaccines is a history of anaphylaxis to a vaccine component or following a previous dose of the vaccine. Health professionals should feel confident in accepting national recommendations and, if in doubt, should refer children for an expert opinion, rather than deny a child protection against a serious infection.