This study investigates how exogenous and endogenous uncertainty influence venture capital (VC) firms’ strategies when investing in an emerging sector. We theorize that greater levels of exogenous uncertainty increase VC firms’ propensity to spread their investments across multiple new technologies and that this effect is mitigated by the endogenous uncertainty they experience. Our empirical investigation of the strategies of 172 U.S. VC firms that invested in clean energy during 1990-2008 provides some support for these arguments. We contribute to entrepreneurship theory and practice by examining the interplay between exogenous and endogenous uncertainty in influencing VC investment strategies in emerging sectors.