Social discrimination in a personnel-selection context was studied using an in-basket exercise. West German participants had to select personnel from an applicant pool that included West German applicants (in-group members) and East German applicants (out-group members). As predicted, we found a main effect for an authority's instruction to discriminate against out-group members. This main effect was, as predicted, qualified by an Instruction Right-Wing Authoritarianism (RWA) interaction effect. Only high scorers on RWA discriminated against out-group members when instructed to do so.