Discussion has focused on the significance of the middle class in Latin America, particularly its relation to social change. In the present study certain hypotheses were tested by interviews in a lower- and middle-class sample of 229 Bogota residents. These hypotheses were concerned with social participation, traditionalism versus rationality, past-versus future-orientation, and mobility and adjustment indices. The findings suggest that aspects of change-orientation are found more with the middle than with the lower class, although not always to the same degree.