In spontaneously hypertensive (strain SHR) and normotensive (strain WKY) rats was studied the elaboration of conditioned reflex of active avoidance in shuttle box. In case when the shuttle box was divided by a partition the SHR rats learned worse than WKY rats. In shuttle chamber without partition the SHR rats, on the contrary, learned better that WKY ones. Such character of interlinear differences can be connected with properties of formation of the instrumental habit of deliverance from electropainful stimulus, because the presence of partition significantly hampered its fulfillment. The obtained results, compared with literature data, testify to the fact that differences of SHR and WKY rats in elaboration of conditioned reflexes are explained basically by the properties of their unconditioned activity and not of the associative processes.