Dissociation is produced by injections of phenazepam (a benzodiazepine tranquilizer) before daily sessions of rat learning in a T-maze. The drinking reflex is seen only after the administration of benzodiazepine. The dissociation depth is linked with the dose of phenazepam: the higher the dose the more pronounced dissociation. Besides, it depends on the time between the administration of phenazepam and the reflex registration. One may assume that learning in the presence of phenazepam gives rise to new interrelations that form the basis for a new functional system which warrants the activity with the drug in the body.