Until recently, little was known about kinship care in the UK. Research has begun to illuminate the circumstances which lead to children being cared for by relatives, and the stresses and strains experienced by carers. However, most UK research has only considered ‘looked‐after’ children placed with formal approved kinship foster carers, although this group forms the smallest proportion of children in kinship arrangements. In this paper, we use microdata from the 2001 UK Population Census to examine the characteristics of kinship carers and children, and demonstrate that most children in kinship care are growing up in informal unregulated arrangements. Implications for policy and practice are discussed.