Many studies have examined the influence of union density (union members as a percentage of all workers) on earnings in the private sector, but few such studies have looked at the public sector. Using data from the 1991 Current Population Survey, this study estimates the determinants of earnings for state a n d local government employees in both the union a n d nonunion sectors. T h e extent of public sector unionization appears to be positively correlated with earnings for both state and local government workers a n d for those covered a n d not covered by collective agreements. Although the effect for non-covered employees is smaller than that for covered employees, both effects are larger than those typically found in similar estimates for the private sector. T h e authors also find that bargaining structure has some influence on earnings, with the most consistent effect being a positive influence of arbitration on the earnings of local government workers.T he rise of public sector unionism has generated an enormous volume of research on the theoretical and empirical relationships among bargaining laws, union membership, public sector employment, and earnings. The largest share of this literature examines the interplay among the legal environment, bargaining, and union membership. A large secondary share of the research focuses on the influence of *Dale Uelmarl is Associate Professor of Econotnics and John S. Heywood is Professor of Economics, University of Wisconsin-Milwaukee, and J o h n Lund is Professor, School for Workers, University of Wisconsin-Madison. The authors thank Robert Drago, .James Peoples, Robert Valletta, and seminar participants at Northern Illinois University for insightful comments on earlier drafts of this paper. different dispute resolution procedures on earnings; and other studies examine the role played by public sector unionism in determining public sector employment levels.Surprisingly little of this literature, however, examines the relationship between the extent of public sector unionization and the level of public sector earnings. This neglect contrasts sharply with the extensive literature studying the relationship between union density and earnings in the private sector. Numerous studies have found that the extent of unionization posi-