A study of a cohort of children in Maidstone Health Authority examined the reasons for the failure to achieve targets for the uptake of measles immunization. Parents were interviewed before they were notified about measles immunization to determine their attitudes, beliefs and intentions regarding measles immunization and a further review was held with those whose child had no record of the immunization by the age of 20 months. The initial interview showed that most parents have a favourable attitude to measles immunization. However, many lacked knowledge, especially about valid contraindications, and claimed not to have received advice from a doctor or health visitor. The most common reasons for non-uptake of measles immunization were: the child had already had measles, concern about contraindications and delay owing to illness. This points to the importance of increasing doctors' and health visitors' knowledge of Department of Health and Social Security guidelines regarding valid contraindications and to the role of health visitors in promoting uptake. However there is also evidence that the gap between actual and target levels of uptake may be less than official figures suggest.