This prospective controlled trial investigated the efficacy of a manual-based clinical hypnosis intervention in alleviating pain in 80 pediatric cancer patients (6-16 years of age) undergoing regular lumbar punctures. Patients were randomly assigned to 1 of 4 groups: direct hypnosis with standard medical treatment, indirect hypnosis with standard medical treatment, attention control with standard medical treatment, and standard medical treatment alone. Patients in the hypnosis groups reported less pain and anxiety and were rated as demonstrating less behavioral distress than those in the control groups. Direct and indirect suggestions were equally effective, and the level of hypnotizability was significantly associated with treatment benefit in the hypnosis groups. Therapeutic benefit degraded when patients were switched to self-hypnosis. The study indicates that hypnosis is effective in preparing pediatric oncology patients for lumbar puncture, but the presence of the therapist may be critical.