Three-dimensional finite element analyses were performed on the cranium of the horned theropod Carnotaurus sastrei to assess how it would have performed mechanically during biting and frontal butting. This technique proved to be an effective tool to provide a better understanding of the cranial functional morphology of C. sastrei. The analyses indicated that the jaw-closing musculature of C. sastrei would have played a key role in diminishing the stress level on the cranium during biting, particularly for the braincase. Force analyses show that C. sastrei would have had a comparatively weak (and faster than Allosaurus fragillis) muscle-driven bite. The finite element analyses also provide quantitative evidence to suggest that the cranium of C. sastrei could have withstood high velocity impacts to its teeth resulting from a hypothetical hatchet-like biting mode, but could not have endured severe, rapid frontal blows during agonistic encounters.