A number of studies have shown that the scale of social dominance orientation (SDO), used to measure the degree of preference for inequality among social groups, is a predictive measure of social and political attitudes toward stigmatized outgroups. However, the relationship between SDO and discrimination has received little attention. The main goal of this study was to assess the validity of a new computer-based method used to measure discriminatory behaviors in a laboratory setting. An additional goal was to test the mediating role of prejudice in the relation between SDO and discrimination. The results provide a first validation of this new method and demonstrate that the effect of SDO on discrimination is mediated by prejudice.