OBJECTIVES: Large-scale rural-urban labour migration and rapid population ageing are two important demographic developments in China. Both result in a growing number of left-behind rural elderly. The paper investigates the effects of adult children’s rural-urban migration on the health of their left-behind elderly parents in China. METHODS: We use a panel data set constructed from the 2011 and 2013 waves of the China Health and Retirement Longitudinal Study (CHARLS). We employ an instrumental variables (IV) strategy to account for the endogeneity of children's migration decision. We use village level sent-down youth (SDY) numbers as an exogenous source of variation in the likelihood of adult children's migration. To improve the measure we calculate an interaction effect between the SDY number and the GDP growth in the cities where SDY originally came from. RESULTS: A strong first stage result is confirmed in our research for the effect of SDY on individuals’ migration decisions. The preliminary second stage result shows that children’s migration has a positive effect on the left-behind parents’ health outcomes. We argue that the income effect from remittances is the most likely transmission channel of children’s migration on elderly left-behind parents’ health. This explanation is confirmed by studying how the effects differ across socio-demographic sub-groups. We also compare different dimensions of elderly health to provide a detailed picture of the health effects of rural-urban migration in China. CONCLUSIONS: This paper contributes new findings for China to the growing international literature analysing the effects of rural-urban migration on the health of elderly left-behind family members, controlling for self-selection of the migration-decision making. We also provide new evidence on the changing mechanisms of intergenerational support in the context of rapid urbanisation and population ageing in China.