We analyze empirically the effects of urban agglomeration on Italian college graduates’ work possibilities as entrepreneurs three years after graduation. We find that each 100,000 inhabitant-increase in the size of the individual’s province of work reduces the chances of being an entrepreneur by 0.2-0.3 percent. This result holds after controlling for regional fixed effects and is robust to instrumenting urbanization. Province’s competition, urban amenities and dis-amenities, cost of labor, earning differentials between employees and self-employed workers, unemployment rates and value added per capita account for 40 percent of the negative urbanization penalty. Our result cannot be explained by the presence of negative large-city differentials in returns to education either. In fact, as long as they succeed in entering the largest markets, young entrepreneurs are able to reap-off the benefits of urbanization externalities: every 100,000-inhabitant increase in the province's population raises entrepreneurs' net monthly income by 0.2-0.3 percent.