This article examines the influence of resource dependence and institutional processes on post-Civil Rights Act changes in private sector workplace segregation. We use data collected by the U.S. Equal Employment Opportunity Commission from 1966 through 2000 to examine organizations embedded within their firm, industry, local labor market and federal regulatory environments. Sex segregation declines precipitously from 1966 through 2000, but we see little evidence that organizations in the same industrial environment have established a stable pattern of segregation and integration. In other words, sex segregation has not been institutionalized. Race segregation, on the other hand, shows strong and increasing evidence of institutionalization, but weak declines after 1980. Firm visibility, field concentration and federal contractor density, but not direct federal affirmative action reporting, prove to be particularly important for understanding changes in segregation levels and institutionalization within industries. Results point to the importance of organizational fields and labor queues for motivating both persistence and change in workplace inequality. (Contains 5 tables and 7 notes.)