Utilizing data for blacks, Mexican Americans, Puerto Ricans, and other Spanish heritage Americans, a model of urban differentiation was evaluated. Building on recent research of black-white patterns, the model related some structural characteristics of metropolitan areas (manufacturing employment, the presence of two important minorities, recent increases in the size of a minority, population size, and region) to educational, occupational, and income differentiation. The overall results suggested the model's utility. Differentiation in 1970, measured by the index of dissimilarity between two percentage distributions, was highest between Puerto Ricans and Anglos in the Middle Atlantic states and between blacks and Anglos in the South. Four separate analyses indicated the importance of occupational differentiation and particularly educational differentiation in influencing income differentiation. The regional analyses showed manufacturing employment to be particularly important in lowering black-Anglo differentiation; percent black in lowering Puerto Rican differentiation (in contrast to expectations about the impact of interminority competition); percent Spanish heritage minority in raising Latino-Anglo differentiation in the Southwest (an index of Anglo gains from Latino subordination); and area population size in lowering Latino-Anglo differentiation elsewhere. (Author/NQ)