Justification. The Terror Management Theory (TMT) posits that Mortality Salience (MS) creates an anxiety state that people deal with through a Worldview Defence (WD) and the adherence to Identity Motives (IM). Objective. To analyse the effects of MS in the WD and IM of Catholics and Atheists from Lima-Peru. Method. A quasi – experimental design was conducted, 2 x 2 [Condition: Experimental versus Control X Belief Group: Catholics (n = 39) versus Atheists (n = 32)]. Participants in the experimental condition were exposed to MS, whereas those in the control condition were not; after which both groups answered the WD and IM questionaries. Results. No significant differences were found in WD and IM between conditions, nor due to the interaction between condition and belief group. However, an analysis of the differences between belief groups indicates that Atheists show higher WD and Catholics, higher levels in the IM of Belonging and Continuity. Discussion. The findings about the MS effects on the dependent variables are consistent with previous results in non-anglo-saxon contexts. Additionally, the differences between belief groups are discussed from an Intergroup Relations framework in the Peruvian context.