The Threat Simulation Theory (TST) postulates that dreaming evolved as a mental simulation for the rehearsal of the neurocognitive mechanisms essential for threat recognition and avoidance behaviors. In the present study, we tested the predictions of the TST that dreams are specialized in the frequent simulation of realistic and severe threatening events targeted against the dream self, and that the dream self is likely to take appropriate defensive actions against the threat. The subjects were 50 Swedish university students who kept home-based dream diaries for a period of two or four weeks. The dreams were analyzed with a content analysis method specifically designed for identifying and classifying threatening events in dreams, the Dream Threat Scale. Our results show that in the dreams of ordinary young adults threatening events are frequent, severe, realistic and targeted against the self and significant others. Appropriate defensive actions are frequently undertaken when the situation allows active participation. The present study replicates earlier findings but in an independent sample, collected in a different country and language area, and analyzed by judges different from the original study. Our findings thus offer further support for the predictions of the TST.