Marxian class categories have been almost totally ignored in systematic quantitative studies of social stratification and income inequality. Occupational status or a similar variable is almost always used as the core criterion defining the individual's position in the system of stratification. This study provides a preliminary operationalization of the Marxian class categories for use in quantitative research. The three most important of these classes--workers, managers and employers--then are analyzed to see what interactions occur between class position and the usual variables used in predicting income (education, occupational status, age and job tenure) and between class and race-sex categories. It was found that there is a substantial interaction between class position and the income returns to education; within class categories, however, there are no differences between race and sex groups in the returns to education.