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.