Those Native American tribes which did not disappear or disintegrate as a result of their contact with Western invaders are currently undergoing the demographic transition. Like most of the world’s pre-industrial peoples they have experienced a dramatic fall in their traditionally high death rates followed by an accelerated period of population growth. The degree to which traditional fertility patterns have responded to these changes has proved to be somewhat easier to determine in the case of select Native American groups than it often is in other parts of the world because most tribes are small, geographically concentrated, and encapsulated in an advanced bureaucratic state. But the relative ease with which contemporary demographic change can be observed and analyzed, is not paralleled by a similar situation with respect to the earlier stages of the demographic transition. Little is known about the demographic situation prevailing among most tribal groups in the early stages of demographic transition when mortality rates began a sustained decline (generally the 1930s). Next to nothing is known about overall tribal mortality and fertility patterns in the decades immediately preceding the formal onset of the transition. Hence it is not presently possible to explore the extent to which traditional demographic differences between tribal groups have been and may still be influencing present differences in demographic response patterns.