We studied the effect of functional inactivation of cerebellar vermis after injection of tetrodotoxin on the formation, consolidation/storage, and retrieval of long-term memory on the model of acoustic startle reaction extinction and freezing behavior in adult rats. Tetrodotoxin administered before training suppressed short-term sensitization of the acoustic startle reaction with subsequent impairment of long-term habituation and formation of conditioned freezing. Application of tetrodotoxin after training or before testing did not modulate the formation and reproduction of the studied forms of defense behavior. Two applications of the drug (before training and testing) caused no disorders in the long-term extinction of the acoustic startle reaction and freezing behavior, which attests to the possibility of dissociated training under conditions of cerebellar inactivation. These data indicate the involvement of the vermis cortex into the mechanisms of long-term memory of various forms of defense behavior.