This study tested whether a hypnosis-based intervention showed promise as a treatment for patients with conversion disorder, motor type. Forty-four outpatients with conversion disorder, motor type, or somatization disorder with motor conversion symptoms, were randomly assigned to a hypnosis or a waiting-list condition. The hypnosis-condition patients were more improved relative to baseline and the waiting-list controls. Improvement was evident on an observational index of behavioral symptoms associated with the motor conversion and on an interview measure of extent of motor disability. No effect was obtained on a nonspecific measure of broad psychopathology immediately posttreatment. At 6-month follow-up, improvement was maintained across the behavioral and interview measures. The effect size of hypnotizability as a predictor of treatment outcome was comparable to that found for other individual patient differences associated with psychotherapy outcome although non-significant. Hypnotizability scored above patient expectations as a predictor of treatment outcome.