Ninety-two ambulatory patients being treated with chemotherapeutic drugs for histologically confirmed cancer who had developed nausea in anticipation of treatment were assigned to one of four conditions: (1) systematic desensitization, (2) relaxation only, (3) Rogerian counseling, and (4) notreatment control. Patients received standard clinic treatment with regard to symptom control. All patients were assessed at two baseline chemotherapy treatments prior to intervention and at two follow-up chemotherapy treatments following intervention. Patients in the first three groups were seen for two 1-hour sessions between successive chemotherapy treatments. Relative to the other three groups, patients given systematic desensitization reported a significant decrease in the severity and duration of anticipatory nausea from baseline to follow-up. Both systematic desensitization and relaxation were found to produce a significant decrease in the duration and severity of posttreatment nausea relative to patients who were not treated or given counseling. These results were found to be independent of patients' ratings of their expectation for success, the credibility of the procedure, or the credibility of the experimenter. Results support a view that systematic desensitization is effective for the control and reduction of anticipatory nausea developed during chemotherapy. Anticipatory side effects are thought to be conditioned. These data support such a view. Results further support a view that both the eliciting stimulus hierarchy and counterconditioned relaxation are required parts of the effectiveness found in the systematic desensitization treatment of anticipatory nausea resulting from chemotherapy.