Purpose – The purpose of this paper is to examine the reasons that children migrate without a parent. Design/methodology/approach – The economic components of the answer to this question are considered by examining the correlates of out-migration for children under 15 whose mothers reside in Bihar and Uttar Pradesh, India. Findings – In this data 1 million children appear to have migrated away from home. On average 3 per cent of living children aged 5-14 in the communities are away from home, but the fraction of out-migrant children ranges between 0 and 29 per cent. The data are found to be consistent with a classical view of migration: children on average appear to migrate out of competitive, rural child labor markets for net financial gain. Practical implications – The costs of migration are important. Children are less likely to migrate from more remote locations. Children are less likely to migrate from locations where child wages are higher. Overall, patterns of child migration away from their mothers look similar to what other researchers have observed in adult populations in different social and economic contexts. Originality/value – The paper considers the determinants of child migration