This paper evaluates the fiscal effect of international migration. It first esti-mates a structural Vector Autoregressive model on a panel of 19 OECD countries over the period 1980-2015, in order to quantify the impact of a migration shock. Empirical results suggest that international migration had a positive impact on the economic and fiscal performance of OECD countries. It then proposes an origi-nal theoretical framework that highlights the importance of both the demographic structure and the intergenerational public transfers. Hence, OECD countries seems to have benefited from a “demographic dividend” of international migration since 1980.