This paper presents seven ethical principles associated with the implementation of immunisation programs. For a public health immunisation program to be ethically justifiable, its principles and operation should be based on sound ethical values: the program should benefit the individual and the community; targeted diseases should be sufficiently severe and frequent to justify the risks and expense of the program, and vulnerable groups within the population should be targeted. The principles also deal with the obligation to monitor for adverse events and for disease incidence to ensure safety and effectiveness. When immunisations are voluntary, vaccine recipients or their parents or carers should be given sufficient information to make autonomous, informed decisions and incentives to participate in public health immunisation programs should not be coercive. Public health immunisation programs depend on mutual trust, which may be threatened by circumstances such as excessive media publicity about adverse events associated with vaccines.