The timing of immunisations for preterm infants is controversial. Because of the statement by the British Paediatric Association/Joint Committee on Vaccination and Immunisation Liaison group that immunisations should normally begin three months after the date of birth, the records of all infants born in 1984 and currently (June 1986) resident in the London Borough of Newham were studied to find out if this recommendation was being implemented. Subjects were divided into groups by birth weight and where possible by gestational age. Cumulative uptakes by age of any component of the first and third triple immunisations, and of the pertussis component, were plotted separately. Comparison of uptake of the first course showed a considerable initial delay for infants weighing less than 2000 g at birth compared with heavier babies, but by 18 months the coverage was almost identical. This difference was not evident for the third course. A similar delay was apparent when infants of 37 weeks' gestation or less were compared with babies born at full term, though recording of gestational age was incomplete. Final overall uptake was poor for all groups. Differences among groups in numbers consenting were not an important factor. Informing those responsible for giving the immunisations of these findings has stimulated their interest in improving practice by implementing the recommendations.