This paper examines child migration in Argentina, Chile and South Africa. It defines child migrants as under 18 year olds whose usual residence was in a different country or province five years prior to census. It estimates the scale of child migration; compares relative magnitudes of internal and international migration; and considers sensitivity to alternative definitions of migration. it also looks at the family structures within which migrant children live at destinations, defining children who are co-resident with adult parents and siblings as dependent, and those outside of these close family members, as independent. Finally, the internal/international and in/dependent distinctions are analysed to describe social-economic characteristics of the four sub-groups of migrant children.