The aim of this paper is to identify the determinants of the income of the employees of the sugarcane sector, and also for the sugar and ethanol industries. Special attention is given to union's role. Earnings equations were estimated for these sectors and information on union's action were collected in a field research. In the regressions estimated, the coefficients of the following variables were significant and had the expected signs: (i) gender (ii) region, (iii) education, (iv) threshold effect of education, (v) membership to labor unions. It was verified the existence and also the influence of labor unions on wage formation
