I reexamine trends in the strength and structure of occupational sex segregation in the United States from 1910 to 1990. Log-multiplicative models show significant change in the association between gender and occupation. Contrary to conventional characterizations, a substantial proportion of this change occurred before 1970. Likewise, a margin-free index shows more integration over the century than do conventional indices. These discrepancies arise from occupation-specific variations in the trajectory of sex segregation: Highly segregated occupations were especially likely to integrate between 1930 and 1940. I identify regions of the occupational structure and pivotal periods in which shifts in segregation occurred and compare these results with conventional historical accounts.