Entrepreneurship holds the key to poverty alleviation and economic development. We find entrepreneurial impact as indicated by the number of jobs created by an entrepreneur is predicted by a biological factor – prenatal exposure to testosterone and a psychological factor – need for achievement. In a sample of 64 male German entrepreneurs we find that the interaction between prenatal exposure to testosterone and need for achievement predicted entrepreneurial impact. This study supports the idea that biological and psychological approaches need to be combined to explain social phenomena