Experiments were carried out in rat strains selected for high (KHA) and low (KLA) rates of active avoidance conditioning in a shuttle box. The elevated plus-maze was used for anxiety measurements. Naive KHA rats, as compared with KLA ones, demonstrated much higher anxiety scores. Inescapable electric footshock had opposite effects on anxiety levels in KHA and KLA rats, i.e., it increased anxiety scores in KLA rats and decreased in KHA. The results point to the role of anxiety in adaptive behaviour, e.g., in learning abilities.