This paper analyzes the effects of different labor market institutions on inflation and output volatility. The eurozone offers an unprecedented experiment for this exercise: since 1999, no national monetary policies have been implemented that could account for volatility differences across member states, but labor market characteristics have remained very diverse. We use a New Keynesian model with unemployment to predict the effects of different labor market institutions on macroeconomic volatilities. In our subsequent empirical estimations, we find that higher labor turnover costs have a statistically significant negative effect on output volatility, while replacement rates have a positive effect, both of which are in line with theory. While labor market institutions have a large effect on output volatility, they do not seem to have much of an effect on inflation volatility, which can also be rationalized by our theoretical model.