This paper describes a study using a postal survey which was sent to health visitors throughout the UK to ascertain their knowledge, and the accessibility, of services used by young families in the areas in which health visitors practiced. The survey was an enhancement to the UK's most recent longitudinal birth cohort study--the Millennium Cohort Study. We studied differences in service accessibility between UK countries, and between areas within countries in terms of poverty levels ('advantaged' versus 'disadvantaged' electoral wards) and high ethnic minority populations. A total of 302 health visitors supplied information on childcare, health, family support and leisure services, and on local statutory initiatives (69 per cent response). Results showed that there were no great differences within countries by type of area, and that families in Northern Ireland had overall access to fewer services. It was apparent that health visitors' awareness of local service accessibility was good but they were less aware of local statutory initiatives.