The Norwegian Parliament passed new rules for child maintenance determination in 2001. This article discusses the 2001 reform, and the debate preceding it, in the light of literature on changing ‘breadwinner assumptions’ in social policy. It is argued that the reform was a clear example of the politicisation of fatherhood in Norway, in that a key concern was to encourage continued care from non-resident fathers. Much less attention was paid to the situation of custodial parents, and to children's material needs. In assuming that parents living apart will conform to the (yet unusual) dual earner/dual carer model, policy makers may be putting undue stress on vulnerable families.