A quasi-experimental study on the effects of terrorism on racial prejudice and ideological orientation is presented. Two independent samples were contacted before and after the Islamic terrorist attacks against railways in Madrid (11 March 2004). Anti-Arab and anti-Semite prejudices, authoritarianism and ideological orientations (liberal against conservative) were evaluated. Results showed that those terrorist attacks provoked changes in a reactionary and conservative direction: stronger prejudices not only against the target group (Arabs), but against another uninvolved group (Jewish); an increase in authoritarianism; stronger attachment to traditional conservative values, and a reduction in the attachment to liberal values. The results are interpreted in terms of the System-Justification Theory, the Motivated Social Cognition model of Conservatism and the Right-Wing Authoritarianism.