This paper investigates the effects of association-style unionism on union membership. In a 1984 Harris poll examining workers' attitudes toward various forms of employee organization, nearly half of all nonunion workers indicated they would join an association, but most of these potential association members said they would not vote for a union to serve as a bargaining agent. Analysis of census data on local government departments strongly suggests, however, that the substitution away from traditional bargaining representation attributable to associations would be followed by an increase in the membership of traditional unions. Specifically, the authors find that in all local government services, the presence of an association in 1977 was a strong predictor of the formation of a bargaining unit by 1982—holding constant other important determinants of public employee unionism, including the legal environment.