Objectives <p>This study aimed to determine the effect of ego depletion (i.e. mental fatigue or self-control exhaustion) on hostage and crisis negotiators’ capacity to communicate empathy.</p> Methods <p> Two randomized controlled experiments with a within-subjects design assessed the ego depletion effect on 52 police negotiators during a simulated hostage situation. Experiment 1 employed a validated manipulation task established in ego depletion literature, while Experiment 2 used the cold pressor task, borrowed from medical literature. Empathy was measured using self-reports, validated third-party assessments, and testing.</p> Results <p> Experiment 1 failed to induce ego depletion, while Experiment 2 successfully induced ego depletion. However, no statistically significant differences in empathy were observed between experimental and control conditions.</p> Conclusions <p> The findings do not provide evidence that ego depletion reduces empathic responding in crisis negotiators under the conditions tested. Instead, they suggest that any effects of ego depletion on empathy may be context-dependent. Factors such as training and professional role may play a moderating role, although these were not directly examined. Accordingly, the results should be interpreted as exploratory and highlight the need for further research.</p>