To establish a series of derived relations between arbitrary stimuli, 20 subjects were exposed to nonarbitrary and arbitrary relational training and testing procedures. Subjects were then exposed to an avoidance conditioning procedure in which one member from each relation was established as a discriminative stimulus for avoidance and nonavoidance, respectively. Subjects who showed conditioned avoidance and nonavoidance also showed derived avoidance and nonawidance to other relation members. All subjects were then exposed to one of two extinction procedures, in which the original discriminative stimuli or other class members were employed, respectively. The majority of subjects exposed to both procedures also demonstrated spontaneous derived extinction of avoidance responding. These findings may have several important treatment implications.