Three experimental studies investigated whether death-thoughts avoidance as a consequence of mortality salience and need for certainty as a consequence of uncertainty are two different motivational states. The results suggest that although death-thought avoidance and need for certainty are different constructs, they share a great deal of variance (anxiety plays a pivotal mediational role in both). However, whereas the impact of uncertainty on negative attitudes towards an out-group with different worldviews (Arabs) was mediated only by anxiety (measured retrospectively), the effect of mortality salience was mediated by both retrospective anxiety and death-thought accessibility. These findings imply that similar effects that have been obtained by these two manipulations are, at least partly, the result of different processes. Copyright © 2013 John Wiley & Sons, Ltd.