The authors report the successful treatment of twenty-four snake-phobic subjects, utilizing a desensitization technique, in which the subjects, under hypnosis, were conditioned to respond to the phobic object in ways that inhibited or were incompatible with anxiety (i.e., muscular relaxation, approach rather than avoidance). From results at the termination of the experiment and six-month follow-up studies, the authors conclude that: 1, it is not necessary to explore with the subject the factors contributing to the learning of a phobia or its unconscious meaning in order to eliminate the fear behavior; 2, the form of treatment employed did not lead to symptom substitution or create new disturbances of behavior; and 3, in reducing phobic behavior it is not necessary to change basic attitudes and values or attempt to modify the personality as a whole. The unlearning of phobic behavior appears to be analogous to the elimination of other responses from a subject's behavior repertoire.