Most archeologists analyzing multiperiod sites eventually deal in some way with the problem of community growth. This chapter aims to compare the growth patterns of some communities in the Valley of Oaxaca, which were specifically studied with this problem in mind. The pattern of community size and growth at Tierras Largas holds for many Early and Middle Formative hamlets in the Valley of Oaxaca. Population growth may be considered as a primary process in the cause-and-effect network with competition and cooperation as derivative processes. It has been suggested by many anthropologists that population pressure, resulting from population growth, is the driving force behind the evolution of the state. Population pressure, expressed in terms of a correlation between settlement size and productive potential, apparently did exist in the eastern Valley of Mexico during the Terminal Formative. A general condition of overpopulation in the Valley of Mexico during the Formative period may never have been a factor.