This paper tests for the existence of structurally different compensating payments in the union and nonunion sectors of the economy. Significant differences may stem from the different mechanisms by which such payments are determined: markets are the primary mechanism in the nonunion sector, while Political processes play a major role in the union sector. The empirical results provide tentative support for the structural differences hypothesis; They also reveal an absence of positive and significant compensating payments in nonunion labor markets.