Most high-income countries will experience declines in their populations over the next few decades. Some negative consequences of aging are on the horizon: greater fiscal imbalances and risks of economic stagnation. Immigration may be a way for those countries to mitigate the tendency. On the source side of immigration flows, brain drain is a risk. The policy paper presents the case of Japan, a nation that has grappled with the consequences of a declining and aging population for several years, as an example for other countries destined to confront similar circumstances in the forthcoming decades.