Large disparities between blacks and whites in both earnings and income have persisted during the period since World War II. In this paper estimates are presented of the contribution of labor market discrimination to the earnings differential. Lower and upper bounds on this contribution are set. Also measured is the extent to which labor market discrimination varies in severity among workers with high and low earning capacities; earnings variations by sex, as well as by race, are discussed in this context. The statistical methodology employed in this study is described in detail, and examined as to its reliability. Based upon data analyzed according to the methodology of this work, it is noted that eliminating labor market discrimination would erase from 30 to 39 percent of the total black-white earnings gap. (Author/GC)