In the pre-school years sleep problems are one of the most common subjects on which parents seek advice from health professionals. In the majority of cases a sleepless child causes significant stress within the family, and if parents do not obtain sufficient sleep this can have a detrimental effect on their physical and emotional well-being. In a small number of cases a child who wakes frequently and will not settle back to sleep may be at risk of physical abuse. In recent years it has been suggested that it may be possible to prevent sleep problems developing by providing parents with advice in the post-natal period. Parents have stated that they find this type of intervention helpful, however, there has been no attempt to establish whether a preventive approach is effective. The aim of this research was to evaluate the efficacy of health education in reducing the incidence of sleep problems. Adopting an experimental approach, participants were randomly allocated to a control group or an intervention group. Parental knowledge of sleep and settling behaviour was manipulated when the children in the intervention group were 3 months old. The sleeping behaviour of the infants in both groups was compared 6 months later, when the children were 9 months old. Data was collected from 86 families in the intervention group and 83 families in the control group. A comprehensive analysis of the sleeping behaviour demonstrated that a significantly smaller percentage of babies in the intervention group had settling and night-waking difficulties than in the control group.