Sociologists and urban commentators often portray metropolitan areas as highly segregated by social class and race. We measured the extent of socioeconomic residential segregation in urbanized areas of the United States in 1970, determined whether cities were as segregated as suburban rings, and compared levels of socioeconomic and racial residential segregation. We found moderate levels of residential segregation and socioeconomic groups. Levels of social class segregation varied little from one urbanized area to another and were about the same in central cities and suburban rings. Racial residentail segregation was much greater than the segregation of social classes within either the black or white communities. The extent of racial residential segregation does not vary by educational attainment, occupation, or income.