Graduated in vivo desensitization was used to treat an intense fear of earthworms in a female college student. The participant reported intense physiological anxiety and avoidance behavior in situations where worms could be encountered. Treatment outcome was measured using a behavioral avoidance test (BAT) and the State-Trait Anxiety Inventory (STAI). Exposure therapy sessions required the client to confront a variety of anxiety-producing situations arranged in a hierarchy. Results indicated that at posttreatment the client was able to complete the BAT and was able to complete the fear hierarchy. State anxiety scores as measured by the STAI declined by 50% from pretreatment to posttreatment. In addition, the client reported little subjective anxiety and no avoidance of situations where worms might be present at posttreatment. The client maintained all posttreatment gains at 1-, 5-, and 8-month follow-ups.