Does entrepreneurship cause urban economic growth and if so how large is the impact? Empirical analysis of such question is hampered by endogeneity. This paper uses two different sets of variables – the homestead exemption levels in state bankruptcy laws from 1975 and the share of MSA overlaying aquifers - to instrument for entrepreneurship and examine urban growth between 1993 and 2002. Despite using different sets of instrumental variables, the ranges of 2SLS estimates are similar, further supporting the significant impact of entrepreneurship on urban growth. I find that a ten percent increase in the birth of small businesses increases MSA employment by 1.1 to 2.2%, annual payroll by 3.1 to 4.0%, and wages by 1.8 to 2.0% after ten years. Furthermore, an accounting exercise at the MSA level indicates that the employment and payroll growth from entrepreneurship are not confined to the newly created businesses but spillover to the aggregate urban economy.