This article presents a framework within which the effects of demographic change on both agglomeration and growth of economic activities can be analyzed. I introduce an overlapping generation structure into a New Economic Geography model with endogenous growth due to learning spillovers and focus on the effects of demographic structures on long-run equilibrium outcomes and stability properties. First, life-time uncertainty is shown to decrease long-run economic growth perspectives. In doing so, it also mitigates the pro-growth effects of agglomeration resulting from the localized nature of learning externalities. Second, the turnover of generations acts as a dispersion force whose anti-agglomerative effects are, however, dampened by the growth-linked circular causality being present as long as interregional knowledge spillovers are not perfect. Finally, lifetime uncertainty also reduces the possibility that agglomeration is the result of a self-fulfilling prophecy. (author's abstract) / Series: Department of Economics Working Paper Series