This paper uses a logit analysis to develop a new index for measuring occupational segregation by race and gender. The authors use the 'L Index' to decompose race and gender segregation into two components: the 'race' and 'gender' components, and the components attributable to the race-gender distribution of residence, education, age, and public-sector employment. They present results for the 1970s and 1980s. The authors' analysis suggests that gender-based occupational segregation increased within occupational categories in the 1980s and that within gender groups, black men were more segregated by race than black women in the 1980s. Copyright 1996 by MIT Press.