In this paper, we look for long-run and short-run effects of fiscal deficits on economic growth and welfare in a standard endogenous growth model. We show that, under very general hypotheses, the Golden Rule of Public Finance”, which allows a government to run a deficit if this deficit is devoted to public investment, leads to a lower balanced growth path in the long-run, and eventually in the short-run. Welfare effects are more difficult to assess. Our model shows that fiscal deficit rules like the Golden Rule may improve or weaken intertemporal welfare, depending on parameter values, and especially on the value of the consumption elasticity of substitution.Classification JEL : H62, H63, E62