Previous studies suggested that the use of a baby-enrolment and reminder system for early childhood immunisation increased public immunisation clinic attendance. It was decided to run a trial to assess the effects of introducing a baby-enrolment program on attendances at local government immunisation clinics. Enrolment leaflets were distributed to each mother of a new child in six areas of greater Sydney while the mother was in the postnatal ward of the local hospital. Clinic attendance figures were monitored, interviews were conducted with mothers as well as professionals involved in early childhood health services, and the conduct of clinics was observed. The trial failed to increase attendance at public clinics. Mothers' reasons for choice of service, particularly their desire for what they believed to be a more personalised service, and the attitude of the professionals (particularly community nurses) with whom they came in contact were considered to be more influential in determining their use (or lack of use) of public immunisation services. Baby enrolment may be effective in increasing attendance at public immunisation clinics only where there is willing cooperation of all stakeholders in supporting public immunisation services.