The Nurse Family Partnership programme was developed in the USA where it is made available to pregnant young mothers in some socially deprived geographic areas. The related Family Nurse Partnership programme was introduced in England by the Department of Health in 2006 with the aim of improving outcomes for the health, wellbeing and social circumstances of young first-time mothers and their children. Methods / design This multi-centre individually randomised controlled trial will recruit 1600 participants from 18 Primary Care Trusts in England, United Kingdom. The trial will evaluate the effectiveness of Family Nurse Partnership programme and usual care versus usual care for nulliparous pregnant women aged 19 or under, recruited by 24 weeks gestation and followed until the child's second birthday. Data will be collected from participants at baseline, 34-36 weeks gestation, 6, 12, 18 and 24 months following birth. Routine clinical data will be collected from maternity, primary care and hospital episodes statistics. Four primary outcomes are to be reported from the trial: birth weight; prenatal tobacco use; child emergency attendances and/or admissions within two years of birth; second pregnancy within two years of first birth.