Interrelated city-suburbs residential-location equations for middle- and upper-income-class families and for poor families are estimated using cross-sectional data on 87 large metropolitan areas in 1960. We find that residential-location decisions of middle- and upper-income-class families are determined, among other things, by the city-suburbs rent differentials, by fiscal surplus differentials, and (negatively) by the location of poor families; additional hypotheses concerning interactions with family income were suggested and statistically accepted. The location equations for the poor families involved cost and fiscal differentials and a proxy variable for employment opportunities.