A UNICEF Synthesis Report that identifies key determinants of vulnerability among children – including those affected by HIV and AIDS – that can contribute to developing an improved global measure of vulnerable children in the context of HIV and AIDS. Household wealth, a child’s living arrangements, and household adult education emerged as the most powerful and consistent factors associated with key health and social outcomes of child vulnerability. Orphanhood status and the presence of a chronically ill adult in the household are also significant for some outcomes. Orphanhood is significant for schooling, child labor, birth registration and DPT3 vaccine.