In this paper we explore the factors that condition the likelihood that an entrepreneur starts a second firm. We use data from survey responses of 1,789 entrepreneurs to examine firm founding behavior. Results indicate that multiple entrepreneurs differ from single-firm entrepreneurs in certain demographic and educational characteristics prior to starting a first firm. The results also show that the first firms of eventual multiple entrepreneurs differ from the first firms of single-firm only entrepreneurs. Those entrepreneurs with the highest probability of starting a second firm have greater time and access to financial resources to undertake a new venture. Starting a first firm sooner after graduation, being divorced, the first firm being acquired, and raising initial capital for the first firm from angel investors all increase the probability that the entrepreneur will start a second firm.