This paper focuses on initial team size and membership change of new venture teams in two studies: (1) a panel study of 408 emerging ventures, and (2) a cross-sectional study of 124 new ventures. The findings suggest that larger initial team size provides an advantage for new organizations, and that the benefits of adding and dropping team members are contingent on the stage of development of the organization and the dynamism of the environment. Both external environment and team composition factors are associated with turnover in venture teams.