A number of researchers and policy makers have recently argued that the most effective way of dealing with long-run disadvantage and the intergenerational transmission of poverty is through early childhood intervention and in particular policies aimed at supporting the family in early childhood development. In this paper we carry out a randomised evaluation of one such programme aimed at improving the skills and parenting strategies of parents, particularly those who find their child’s behaviour difficult or challenging. Our evaluation shows that the treatment significantly reduced behavioural problems in young children when measured 6 months after the intervention. Furthermore our detailed cost analysis, combined with a consideration of the potential long-run benefits associated with the programme, suggest that the long-run rate of return to society from this programme is likely to be relatively high.