Résumé : The paper contributes to the debate on the stability/efficiency tradeoff of automatic stabilizers. A simple AD-AS two countries model is presented and illustrates circumstances where a reduction in taxes can foster stabilization. The testable implication from the model is that tax cuts can either increase or decrease volatility depending on the structure of the taxation system. Hence, lowering taxes for efficiency purposes may not cost in terms of stabilization. This implication is tested on a sample of 25 OECD countries over the period 1960-1999 taking account of the endogeneity and omitted variables issues identified in the literature. We found acceptably robust evidence that the size of governments in OECD countries has played a stabilizing role for both output and inflation. However, the relationship between government size and macroeconomic stability is not linear. The composition of public finances, in particular the tax mix, matters for output and price volatility. Distorting taxes, namely taxes on labor and capital, might have negative effects on macroeconomic stability. Consequently, the potential trade off between stability and flexibility might not exist.