The dramatic decline in unionization during the last decade is investigated with the use of survey data from 1977 and 1984. First, it is found that only a small fraction of the decline in unionization can be accounted for by shifts in labor force structure. Second, there has been a substantial drop in demand for union representation among nonunion workers that can be accounted for by an increase in the job satisfaction of nonunion workers and a decrease in nonunion workers' reports that unions improve wages and working conditions. Finally, there has been a substantial increase in employer resistance to unionization that is likely to have made it more difficult for unions to organize even those workers who desire union representation. Increased foreign and increased nonunion domestic competition (particularly in deregulated industries) may be key underlying causes of these changes.