Exposure-based therapies are effective for anxiety disorders, but relapse remains a problem. One explanation might be that exposure therapy reduces threat expectancy but not related feelings of unpleasantness (negative valence of the conditioned stimulus; CS+), which may promote return of threat expectancy and associated fear. Laboratory research has indeed shown that fear extinction leaves negative valence of the conditioned stimulus (CS+) intact. Here, we tested whether adding positive consequences to the CS+ during extinction, a procedure known as counterconditioning, would change the valence of the CS+ and thereby prevent return of threat expectancy. Participants underwent Acquisition (day 1), Intervention (counterconditioning or extinction; day 2), and Spontaneous recovery and Reinstatement (day 3). As expected, threat expectancy ratings during the Spontaneous recovery and Reinstatement tests were lower after counterconditioning than after extinction, but counterconditioning did not reduce CS + negative valence more than extinction. Alternative mechanisms and clinical implications are discussed.